introduction: the process of urbanism in countries that are developing, like islamic republic of iran with increasing of the number and the size of cities and the fast accepting of population have been caused the forming of problems like an in-official economics and in-official settlement and was become creating high population in main and old places of city and increasing of air pollution and ...

In this study growth characteristics of 815 tuwini (Capoeta trutta) in Shour River were investigated during July 2010 through June 2011. The population was composed of 62.94% females and 32.02% males. Sex ratio was 1: 1.96, with significant differences observed at 1:1 (x2= 150.6 df= 1 p < 0.05). The age distribution of this population ranged from

objectives: the object of this research was to investigate the «quality of life» and relation to demographic characteristics in elderly peopel of tehran. methods & materials: the method of this research was a descriptive-correlation. in this research 243 of elder were selected with accessible sampling from people who referred to elder centers, cultural centers, and public parks in deferent dist...

curly top disease is one of the important diseases of sugar beet. spatial pattern and population variation of leafhoppers circulifer haematoceps, and c. tenellus, vectors of sugar beet curly top virus, were studied in hamadan province, iran for three years (2007- 2009). sampling was carried out at the early stage of the plant growth, in accordance with planting date for 9 weeks, in 7- 10 day in...

background: timely access to cardiovascular health services is necessary to prevent heart damages. the present study examined inequality in geographical distribution of cardiovascular health services in iran.   methods: present study is a cross-sectional study conducted using demographic data from all iranian provinces (31 provinces) from 2012 census by the statistics center of iran (sci). the ...

Previous efforts to use the Euler equation to estimate maximum population growth rates (variously symbolized as either r, r(m), or r(max)) have used simplified models of survivorship that neglect differences in survivorship schedules among species. In particular, several recent analyses have used either an exponential model of survivorship or a step function model in which all individuals live ...

Fractional derivative in time variable is introduced into the Fokker-Planck equation of a population growth model. It’s solution, the KNO scaling function, is transformed into the generating function for the multiplicity distribution. Formulas of the factorial moment and the Hj moment are derived from the generating function, which reduces to that of the negative binomial distribution (NBD), if...

We consider a random network evolving in continuous time in which new nodes are born and old may die, and where undirected edges between nodes are created randomly and may also disappear. The node population is Markovian and so is the creation and deletion of edges, given the node population. Each node is equipped with a random social index and the intensity at which a node creates new edges is...