Following Smith¡¯s advocacy of free trade and competition, David Ricardo attempts to strengthen his theory of absolute advantage, which excludes from international trade countries which have no advantages over others, by eliminating this weakness. To do so, Ricardo introduces to the economics...

In this paper, a model is set up to determine the size of the wildlife population compatible with the extraction of the maximum output by rural people from natural resources. It is found that when the size of human population increases, to obtain the maximum output of food, the size of wildlife...

From Arthur Lewis' seminal paper to Michael Todaro's model, there has been an attempt to explain migration from rural to urban areas. However, no attempt has been made to determine the trajectory of employment in a dual economy in order to increase employment. In this paper, we set up a planning...

In the main duopoly models such as that of Cournot, Bertrand and Dixit, the products are homogeneous and the price of one producer is expressed as a function of variables such as the output or the price of the other producer. However, in the real world, products are differentiated and price...

The ongoing debate between proponents of free trade and protectionism stems from the lack of the free trade and protectionism dividing line in manufacturing industries, upon which countries can agree. In this paper, we determine from a duopoly model of differentiated products this trade line,...

In the world trading system, there is a trade of differentiated products among countries due to their specialization in the same line of production. However, in two-by-two models two countries cannot specialize in the same line of production except for strategic reasons and necessarily gain from...

In the economics literature, Heckscher-Ohlin, Melvin and Ricardo's theories based respectively on factor endowments, increasing returns to scale and comparative cost advantage are generally considered as separate theories that explain international trade. In this article, we argue that factor...

During the apartheid era South Africa's internal migration was more or less determined by law. However, new patterns of internal migration have emerged with the democratisation of the country in 1994. These patterns were examined by means of a modified gravity model, which showed that the...

The migratory labor system in South Africa draws large numbers of men away from rural areas and often places them in single sex hostels, prompting contacts with sex workers and the HIV infection of their partners. As inadequate information exists on HIV/AIDS and internal migration's...

There is a voluminous literature on HIV/AIDS and South Africa. However, no study focuses on the modeling of contextual factors concerning HIV/AIDS prevalence in South Africa. In this paper, two models of contextual behavioral risk factors of HIV/AIDS prevalence were developed so that policy...