In this article we study start-up investments in developing countries. Using a representative firm, we wonder how relevant are the effects of taxation and risk on new business activities. It is worth noting that developing countries are usually characterized by three main characteristics....

In order to study the dynamic changes in gas concentration, to reduce gas hazards, and to protect and improve mining safety, a new method is proposed to predict gas concentration. The method is based on the opposite degree algorithm. Priori and posteriori values, opposite degree computation,...