Attempts to describe language competition and extinction in a mathematical way have enjoyed increased popularity recently. In this paper I review recent modeling approaches and, based on these findings, propose a model of reaction-diffusion type. I analyze the dynamics of interactions of a population with two monolingual groups and a group that is bilingual in these two languages. The results s...

This paper presents a model in which agents are distinguished by their characteristics, exchange of goods requires communication between firms and their customers, and agents with similar characteristics communicate more effectively. This setup delivers a body of testable implications about the matching of workers to jobs, the associated wages and product prices, and the manner in which job ass...

Introduction According to the World Health Organization (WHO), overweight and obesity are defined as abnormal or excessive fat accumulation that may impair health [1]. Overweight and obesity are usually diagnosed when weight normalized for height, or body mass index (BMI: weight in kilograms divided by the square of the height in meters, kg/m2), exceeds a defined threshold. In 1995, the WHO pro...

357 June 2013, Vol. 103, No. 6 SAMJ Feline companions and demography To the Editor: In A Moveable Feast by Ernest Hemingway, the author goes to visit Gertrude Stein and, sitting downstairs, hears from above the following by Ms Stein: ‘Don’t, pussy. Don’t. Don’t, please don’t. I’ll do everything, pussy, pussy, but please don’t do it. Please don’t. Please don’t, pussy.’ Hemingway immediately leav...

conclusions the prevalence of ms showed an increasing rate of the disease in recent years. decreasing of the female to male ratio and patients’ low socio-economic level, need more studies. the increasing rate of patients with progressive relapsing feature and more disabled patients belong to this subtype show the poor prognosis. results a total of 142 patients were participated in this study. p...

conclusions the findings suggested that according to the ecological conditions of ahvaz, a family history of ms may increase the risk of developing ms. results in both cases and controls, no significant associations were found between arab ethnicity and incidence of ms, marital status and risk of ms in ahvaz, or more than 15-year residency in ahvaz, birth in khuzestan, and month of birth and th...

the diamondback moth, plutella xylostella (l.) (lep.: plutellidae) is one of the most destructive insectpests of cruciferous crops throughout the world. in this research, the demographic parameters of p. xylostellawere studied on five rapeseed cultivars including licord, modena, okapi, rgsoo3 and regxkobra. theexperiments were conducted in a growth chamber at temperature of 25 â± 1â°c, 60 â± 5%...