in this paper, we explore a nonlinear mathematical model to study the spread of asthma due to inhaled pollutants from industry as well as tobacco smoke from smokers in a variable size population. the model is analyzed using stability theory of differential equations and computer simulation. it is shown that with an increase in the level of air pollutants concentration, the asthmatic (diseased) ...

In this paper, we study relation and impact of social capital on organizational commitment among staffs of Islamic Azad University, Branch of Ayatollah Amoli. The data required were collected by using field (survey) research method and the questionary tool. Statistical population was included 152 subjects that 108 subjects were selected based on Morgan table. The descriptive results show that c...

We analyze the equilibrium spread when the transaction size of informed traders is elastic in the value of private information (α). We show that the pooling equilibrium is likely to be inefficient when trade size is sensitive to α and the inefficient equilibrium can occur before the market breaks down. The pooling equilibrium spread does not monotonically increase with α, although it increases ...

a r t i c l e i n f o In this work we propose a simple market model where some features of the Specialist System are analyzed. In particular, the specialist's obligation to display bid/ask quotes on the book within the bounds imposed by the Exchange is considered. The proposed model allows to analyze the effects of the specialist's interventions on the short term dynamics of bid/ask prices and ...

In this paper we present an extended model for the estimation of effective bid-ask spread that improves the existing models and offers a new direction of generalisation. The quoted bid-ask spread represents the prices available at a given time for transactions only up to some relatively small amount. Moreover, it is observed that large trades are usually made at “worse” prices. Thus, we extend ...