This study evaluates the impact of armed conflict on school enrollment across 37 Sub-Saharan African countries from 1990 to 2023. Using entropy balancing and fixed effects panel regression, the study finds that conflict reduces gross primary enrollment by 0.9 to 1.1 percentage points. Girls experience greater enrollment losses than boys and remain depressed three years after conflict ends, whereas boys recover within that window. Central Africa suffers a 3.0 percentage point penalty, while West Africa shows statistically insignificant effects. Control of corruption fully neutralizes the conflict penalty at a threshold corresponding to the governance levels of Ghana and Senegal. Policy should prioritize legally ring fenced education budgets and anti-corruption measures during and after conflict.
Oyebamiji Sodiq Akorede, Adeyemi Paul Oluwatimilehin, Adedeji Teslim Olaide, Akinyemi Akeem Alabi, Ruth Sinmilejesu Alesinloye
This study examines portfolio optimization and financial risk analysis for ten large-cap U.S. equities drawn from seven GICS sectors of the S&P 500, covering the period January 2021 to December 2025. Motivated by the well-documented limitations of classical mean-variance (MV) optimization (including sensitivity to return estimation error and the systematic underestimation of tail risk in non-normal return environments), the study adopts an integrated quantitative and computational framework comprising LASSO regression-based return prediction, Markowitz MV optimization, historical Value-at-Risk (VaR), Conditional Value-at-Risk (CVaR), and Monte Carlo simulation. Three portfolio strategies are constructed and evaluated which included a Classical MVO portfolio using historical mean returns, a Machine Learning-Enhanced portfolio substituting LASSO-predicted returns as expected return inputs, and an Equal-Weight benchmark. Results indicate that both optimized portfolios substantially outperform the Equal-Weight benchmark on a risk-adjusted basis, achieving Sharpe ratios of 1.374 and 1.317 respectively against the benchmark's 0.826. The ML-Enhanced portfolio generates the highest mean simulated five-year terminal wealth of 4.037 times the initial investment, with a near-zero probability of capital loss (0.05%) compared to 0.75% for the Equal-Weight strategy. Individual firm risk analysis reveals pronounced tail-risk heterogeneity, with Amazon recording the most extreme 99% CVaR of −25.210% and Coca-Cola the most resilient at −5.964%. The systematic divergence between VaR and CVaR estimates across all entities provides direct empirical support for CVaR's theoretical superiority as a risk measure in leptokurtic return environments which affirm the value of integrating machine learning with classical optimization theory and tail-sensitive risk measurement for evidence-based portfolio construction.
Nonye Peculiar Okafor, Melitus A. Oyigbo, Jude C. Nwakamma, and Magaret Ada Maduka
Physical activity is essential for children’s physical, psychological, social, and overall development, yet participation among primary school children may be constrained by institutional, teacher-related, and pupil-related factors. This study investigated the perceived barriers affecting children’s participation in physical activities in primary schools in Owerri North Local Government Area (LGA) of Imo State, Nigeria. The study adopted a descriptive survey research design. The population comprised 410 primary school teachers, from which a sample of 202 teachers was determined using the Taro Yamane formula at a 0.05 level of precision and selected through a multistage sampling procedure. Data were collected using a structured questionnaire titled Barriers to Physical Activity Questionnaire (BPAQ). The instrument was subjected to face and content validation by experts in Physical and Health Education and Measurement and Evaluation, while its reliability was established using Cronbach’s alpha coefficient, yielding a coefficient of 0.83. Data were analysed using frequency counts, percentages, mean, and standard deviation. The findings revealed that inadequate funding, inadequate support from school management, inadequate access to sports facilities and equipment, poor allocation of instructional time, and inadequate teaching spaces were major institutional barriers. The study concluded that participation in physical activities, among children in primary schools in Owerri North LGA, is constrained by interconnected institutional, teacher-related, and pupil-related factors. It recommends improved funding and provision of facilities and equipment, stronger administrative support, adequate instructional time, continuous teacher professional development, and the adoption of engaging and inclusive strategies to motivate pupils’ participation in physical activities.