We introduce a model for the dynamics of a patchy population in a stochastic environment and derive a criterion for its persistence. This criterion is based on the geometric mean (GM) through time of the spatial-arithmetic mean of growth rates. For the population to persist, the GM has to be >/=1. The GM increases with the number of patches (because the sampling error is reduced) and decreases ...

background: hemophilia is the most frequent severe hereditary hemorrhagic disease due to deficiency of coagulation factors viii (hemophilia a) or ix (hemophilia b) in plasma. we aimed to identify patients with hemophilia in kermanshah, iran and assess the incidence of inhibitors in this population and its associated factors. methods: this study was conducted on patients with hemophilia a and b ...

Khoshnevisan et al. (2007) proposed a general family of estimators for population mean using known value of some population parameters in simple random sampling. The objective of this paper is to propose a family of combined-type estimators in stratified random sampling adapting the family of estimators proposed by Khoshnevisan et al. (2007) under non-response. The properties of proposed family...

This paper proposes two sampling strategies based on the modified ratio estimator using the population mean of auxiliary variable and population correlation coefficient between the study variable and the auxiliary variable by Singh and Tailor (2003) for estimating the population mean (total) of the study variable in a finite population. A comparative study is made with usual sampling strategies...

this research compares the psychological well-being of female heads of household and woman in male-headed in city of tehran. it was a descriptive cross-sectional study. statistical population was consisted of female heads of family under coverage of imam khomeini aid committee and woman in male-headed households in city of tehran in 2012. the sample consisted of 280 subjects including 140 femal...

the fact that life styles and personal interests, aggregate within families suggests that shared environment in addition to shared bioligical factors could play a role in determining the phenotypic similarity of idividuals living in the same household. it is a major concern of cardiovascular epidemiologists to know how much of the familial aggregation of blood pressure is attributable to shared...

aim : the present study aimed to evaluate the prevalence of positive family history of these cancers in a large population-based sample of tehran province, capital of iran. background : upper gastrointestinal (ugi) cancers (gastric and esophagus cancer) constitute a major health problem worldwide. a family history of cancer can increase the risk for developing cancer and recognized as one of th...

background: individuals with a positive family history of colorectal cancer have an increased risk of developing this type of cancer. the number of affected relatives and the age at diagnosis are two factors that increase the risk of colorectal cancer. the aim of this study was to assess the prevalence of a positive family history of colorectal cancer in a random sample among the iranian genera...