Farmers’ choice of varieties and demand for improved cassava stems in Nigeria

In this study, we used a household level survey to assess choices of varieties and demand for improved cassava varieties. A multivariate probit model was used to examine the determinants of choice decisions of the farmers for different varieties preventing potential endogeneity and measurement error. A Linearized Almost Ideal Demand System (LA/AIDS) model was used to analyze the demand system for improved cassava varieties. The results of the (LA/AIDS) model indicated farmers were very price sensitive to changes in improved stem prices and incomes. We suggest that intervention program that will improve the purchasing power of the farmers should be targeted towards the smallholder cassava farmers to accelerate adoption of improved cassava varieties. Int. J. Agril. Res. Innov. Tech. 11(2): 42-51, Dec 2021

A FRACTIONAL ORDER HIV/AIDS MODEL USING CAPUTO-FABRIZIO OPERATOR

Background: HIV is a virus that is directed at destroying the human immune system thereby exposing the human body to the risk of been affected by other common illnesses and if it is not treated, it generates a more chronic illness called AIDS. Materials and Methods: In this paper, we employed the fixed-point theory in developing the uniqueness and existence of a solution of fractional order HIV/AIDS model having Caputo-Fabrizio operator. This approach adopted in this work is not conventional when solving biological models by fractional derivatives. Results: The results showed that the model has two equilibrium points namely, disease-free, and endemic equilibrium points, respectively. We showed conditions necessitating the existence of the endemic equilibrium point and showed that the disease-free equilibrium point is locally asymptotically stable. We also tested the stability of our solution using the iterative Laplace transform method on our model which was also shown stable agreeing with the disease-free equilibrium. Conclusions: Numerical simulations of our model showed clear comparison with our analytical results. The numerical solutions show that given fractional operator like the Caputo-Fabrizio operator, it is less noisy and plays a major role in making a precise decision and gives room (‘freedom’) to use data of specific patients as the model can be easily adjusted to accommodate this, as it a better fit for the patients’ data and provide meaningful predictions. Finally, the result showed the advantage of using fractional order derivative in the analysis of the dynamics of HIV/AIDS over the classical case.

Analysis of the Demand for Berries in Mexico: An Application of the Almost Ideal Demand System (AIDS) Model

Objective: To identify the factors affecting the demand for berries in Mexican households, as well as the behavior in face of variations in economic income. Design/Methodology/Approach: In order to analyze the demand, microdata were used from the National Income-Expenditure Survey of Households 2018 (Encuesta Nacional Ingreso Gasto de los Hogares, ENIGH) from the National Institute of Statistics and Geography (Instituto Nacional de Estadística, Geografía e Informática, INEGI), and for its modelling the Almost Ideal Demand System (AIDS) model was used. Results: Because of their Marshallian elasticity, berries are an elastic good (-1.0316), and because of their expenditure elasticity they are a luxury good (1.0691). In terms of crossed Marshallian elasticities, sweet fruits and sugary beverages were identified as substitute goods with elasticity of 0.0013 and 0.0380, respectively, while semi-acid fruits and melons would be complementary goods, with elasticities of -0.0191 and -0.0184, respectively. Study Limitations/Implications: Given that most of the time series of the berries lack disaggregation and sufficient information, it is difficult to analyze each component of the group separately; therefore, it was decided to analyze the group of berries and its relationship with other goods; in addition, the ENIGH database was selected, which provides more information. Conclusions: There are state differences in the response to changes in prices and income with regard to the demand for berries, so that facing a generalized increase in household income consumption would increase much more in the center of the country than in the south-southeast.