University of Douala

The degradation of electric vehicle (EV) batteries in tropical environments is poorly understood in the literature. This study aims to experimentally characterize the degradation of EV lithium-ion batteries and to assess the influence of climatic factors (temperature, humidity, dust) and local driving conditions (road quality, mileage) in the tropical environment of Cameroon. Our contribution lies in providing unique empirical data, obtained from real-world monitoring, specifically adapted for sub-Saharan environments and incorporating variables often overlooked. An on-board experimental device was developed on a test EV, integrating Arduino-compatible sensors (DHT22 for temperature/humidity, Sharp GP2Y1010AU0F for dust, ADXL345 for road quality, Neo-6M for mileage) and an existing battery monitoring module (BMS) (an LTC6811-based data acquisition system for cell voltage and a shunt for current) for continuous collection of battery parameters over two years (SoH, SoC, internal temperature, and internal resistance). The analysis focused on trends in SoH and internal resistance and their correlations with environmental and driving parameters. The results show a gradual degradation of SoH and capacity, as well as an increase in internal resistance. High temperatures, humidity, and dust, as well as poor road quality, are directly correlated with an acceleration of this degradation. In conclusion, tropical climatic conditions and local driving characteristics have a significant impact on the aging of EV batteries. These findings are crucial for the development of adapted BMS and the optimization of EV performance in similar environmental contexts, promoting sustainable mobility in Africa. • First comprehensive analysis of electric vehicle battery degradation in a tropical climate (Cameroon), offering unique insights into real-world performance. • Internal battery temperatures reached critical peaks (up to 55°C), strongly correlating (0.83) with increased internal resistance and accelerated degradation. • Significant thermal inertia was observed between ambient and internal battery temperatures, highlighting sustained thermal stress in hot environments. • Dust accumulation and high ambient humidity are identified as major environmental stressors, exacerbating battery degradation. • Multicollinearity was identified among key environmental variables, necessitating careful statistical consideration for accurate interpretation of individual parameter effects .

Burnout remains a global challenge affecting productivity and wellbeing of students of all academic levels. Despite the harmful effects of burnout among health science students, academic burnout is poorly characterized in the Cameroonian context. The purpose of this study was to assess the prevalence and factors associated with academic burnout among undergraduate health science students of Saint Louis University Institute Douala and Yaoundé Campuses, Cameroon. This was an analytic cross-sectional study carried out at the St. Louis University Institute, Douala and Yaoundé campuses from the 9th of January to the 9th of February 2024. Convenience sampling technique was used to enroll undergraduate health science students. A structured questionnaire was used to collect data on the sociodemographic characteristics and factors associated with burnout. The Burnout Clinical Subtype Questionnaire (BCSQ-12-SS) was used to determine the prevalence of burnout, and the Perceived Stress Scale (PSS) was used to assess perceived stress. Statistical Package for Social Sciences (SPSS) was used for analysis. Multivariate logistic regression was performed to examine the association between the variables and burnout. Among the 570 health science students enrolled in the study, 439 (77%) were females. The most represented age group was between 16 and 25 years, 481 (84.4%). Majority of the study participants, 259 (45.4%) were in level 200, and most, 254 (44.6%) were from the nursing department. The prevalence of burnout was found to be 47% (268/570). Academic workload (p = 0.038), lack of support from friends and teachers (p = 0.046), study and life pressures (p < 0.001), perceived stress (p = 0.041), and school level (p = 0.002) were significantly associated with academic burnout. We report a high prevalence of burnout among undergraduate health science students. Study and life pressures, academic workload, perceived stress, and being a Level one student were found to be significantly associated with burnout. This will help to inform preventive measures by universities to reduce the burnout burden.

ABSTRACT This study examines the role of human capital and its specialization in optimizing climate finance for green innovation in developing countries. By identifying a critical threshold of human capital, this research provides actionable insights for policymakers on how to improve the effectiveness of climate finance in promoting ecological transitions. Dynamic panel analyses using the two‐step system generalized method of moments (GMM) on a sample of 42 countries over 2017–2022 show that climate finance has a conditional negative effect on green innovation intensity and capacity. Human capital adversely affects green innovation below the critical threshold of 0.6. Above this threshold, however, it becomes a significant driver for green innovation, significantly reinforcing the effect of climate finance. Human capital specialization in technical fields (NATS_MSICM), information and communication technologies, and environmental sciences (ENVS_HW) is more conducive to ecological transition than specialization in social sciences, law, and business administration (SOCS_BAL), even though the latter category promotes green innovation intensity. The results suggest that the optimal allocation of skilled human capital to improve the effectiveness of climate finance involves less than 38% in the social sciences (SOCS_BAL) and more than 21%, 22%, and 6% in the fields of NATS_MSICM, ENVS_HW, and ICT, respectively. In light of these findings, developing countries need to improve both the level and quality of their human capital to acquire the skills necessary to initiate the green transition, attract climate finance, and effectively use it to support the transition.

AimsThe optimal duration of antibiotic therapy in joint infection remains controversial, particularly as native joint septic arthritis and periprosthetic joint infection (PJI) differ substantially in pathophysiology, surgical management, and prognosis. While short antibiotic courses have been advocated for native joints after adequate drainage, prolonged therapy is often recommended for PJIs due to biofilm-related infection. This systematic review and meta-analysis of randomized controlled trials (RCTs) aimed to compare short- with long-course antibiotic strategies in both native and prosthetic joint infections.MethodsFollowing PRISMA guidelines, a systematic search was performed across PubMed, Embase, Web of Science, and the Cochrane Library. Only RCTs were included. Studies were assessed for inclusion using predefined population, intervention, comparison, outcomes, and study (PICOS) criteria. Meta-analyses were conducted using MedCalc, and treatment failures were analyzed using odds ratios (ORs) with 95% CIs.ResultsA total of 12 RCTs involving 1,414 patients (native 577; periprosthetic 837) were included, with six eligible for meta-analysis. For PJIs, long-course therapy (≥ 12 weeks) significantly reduced treatment failure compared with short courses (OR 2.04, 95% CI 1.18 to 3.54; p = 0.011), while complication and mortality rates were similar. In contrast, for native joints, short-course therapy (≤ four weeks) achieved comparable infection control with prolonged regimens (OR 1.347; p = 0.565) when combined with adequate surgical drainage, particularly in paediatric populations. Surgical strategy (e.g. debridement, antibiotics, and implant retention vs one- or two-stage exchange) influenced outcomes more than antibiotic duration alone.ConclusionOptimal antibiotic duration should be individualized based on joint type and surgical approach. Short courses are effective for native septic arthritis with proper drainage, whereas PJIs generally require extended therapy due to biofilm-related complexity. We propose the Age-Joint-Immunity-Surgery-Sensitivity (AJISS) score as a decision-making tool to guide treatment duration, warranting prospective validation.Cite this article: Bone Jt Open 2026;7(3):394–406.

The objective of this study is related to a holistic approach underscoring the decisions of SMEs to apply for bank loans. A hybrid or triangulation approach research design was used to achieve the objective of the study. Questionnaires were used to collectdata from 450 SMEs sampled using convenience sampling technique. Logistic regression statistical technique was used to analyse collected data. The results of the study showed that ageof SMEs, sizes of SMEs, number of years in business, business plan, accounting practice, network and relationship with bank(s), internal funds, level of education, business experience, control aversion, optimistic view, interest rate, and collateral significantly influence the decisions of SMEs to apply for bank loans. By implication, to reduce the financing lacuna, it is important to incentiviseSMEs to apply for bank loans by targeting and implementing policies related to characteristics of SMEs, characteristics of owner/managers, and lending conditions.

Background : Recent studies highlight that traditional export theories cannot fully explain Gabon’s export dynamics, as domestic demand plays a crucial role, especially in LDCs. The Single Equation Approach, enhanced by ARDL bounds testing, effectively captures both short- and long-run relationships in this context. Aims: To investigate the relationship between exports and domestic sales in Gabon into the literature the conventional cointegration techniques have been used. Nevertheless one criticism address to these results is that, it’s well known that the asymptotic power of conventional cointegration tests are quite sensitive to the sample size while the standard time frame into the literature is just over 48 oannual observations. Then the aim of this paper is to overcome this criticism. . Method: To tackle this issue since the literature presents the Single Equation Approach as the conventional approach to tackle the small sample bias we relie on ARDL Boud testing. In fact, the main difference among the two (Single Equation Approach and ARDL) is that the second behind to the conventional cointegartion test on the Error Correction Term they have an additioal test of existence of long run relationships among the varaibles the namely Bound test of cointegration. Results: According to the obtained results on 42 annual observations between 1980-2021 the ARDL Modelling fit well the Model underlying the New Export channel in CEMAC with the Gabonese experience. In fact there is a substitution effect between domestic demand and exports with a negative elasticity of around 23%. Concerning the Reverse causation we reach to the conventional result that export performance impacts negatively domestic demand with a negative elasticity of around 56% implying that the country industrializes when it exports grew. Conclusion: The ARDL Bound testing of cointegration is a relevant engine to assess long run relationship among variables or as a system based estimates. In fact, with this study it has proven to be feasible for a wide variety of economic problem as those investigating here for the Gabonese economy.

Cement stabilization is employed to construct pavement layers with available sandy clay soil. This paper aims to demonstrate how curing under ambient hot weather conditions in coastal regions, along with the quality of water used, significantly impacts the targeted strength. The soil is subjected to a curing process at 1%, 2%, 3% and 4% cement dosages. This is conducted under conditions of high relative humidity, ambient weather, and subsequent immersion in pipe-born water or culvert water for a total duration of seven days. Microstructural, geotechnical and mechanical assessments are conducted. X-ray diffraction patterns and scanning electron microscope images revealed the presence of kaolinite, illite and quartz minerals, which produce calcium silicate aluminate hydrate compounds with cement. Energy dispersive X-ray mapping reveals the presence of residual calcium and aluminium compounds on samples that have undergone ambient curing. This phenomenon can be attributed to the rapid deceleration or cessation of hydration reactions, resulting from the premature loss of water through evaporation. Low strength, 0.4 MPa at 3% dosage, were recorded and the samples disperse when immersed. On the other hand, those cured in high relative humidity exceed 1.2 MPa and 1.3 MPa following immersion. The strength of samples immersed in culvert water is lower (1.3 MPa) than those in pipe-born water (1.5 MPa), indicating the negative impact of the carbonate and sulphate compounds in the culvert water. For sub-base pavement layers, the design cement index is 2% for medium traffic and 3% for high traffic roads, with watering during the first seven days.