Time preference has a peculiar role in determining the level of economic activities. Time preferenceis the most important origin of interest rate. In this paper we study the founders and defenders'viewpoints about time preference and then we try to criticize them. It seems that discounting futureutilities is resulting from irrationality and it is ethically indefensible too. From mathematical as...

To the Editor: The Department of Surgery at the Nelson R Mandela School of Medicine is proud of its 100% pass rate in the October 2008 Colleges of Medicine of South Africa examinations held in Durban. Most candidates attended the graduation and joined the 3 who passed in May as registered specialists in general surgery. This represents a stalwart effort on the part of the candidates and their t...

Johansen and Sornette proposes that the crash has fundamentally an endogenous origin and exogenous shocks only serve as triggering factors. This endogenous force is shown in price as power law log-periodicity (PLLP) signature prior to a crash. We estimate the highly nonlinear model developed by them using a hybrid approach which combines scatter search, genetic adaptor and tabu search. The mode...

Digital twins have advanced fast in various industries, but are just emerging postharvest supply chains. A digital twin is a virtual representation of certain product, such as fresh horticultural produce. This linked to the real-world product by sensors supplying data environmental conditions near target fruit or vegetable. Statistical and data-driven quantify how quality loss produce occurs gr...