background: the fourth survey of the surveillance system named ‘‘childhood and adolescence surveillance and prevention of adult non-communicable disease’’ (caspian–iv study), was conducted among a national representative sample of iranian students. this paper describes the methods and early findings of this survey.  methods: this nationwide school-based study was conducted in 31 provinces of ir...

background: the use of chemicals is essential in education resulting in exposure to these pollutant in a variety of chemical and research laboratories. chemical contaminants in chemical laboratories are in different forms and chemical exposure risk assessment is important for choosing appropriate controls in protecting the health of operators, experts and students. for risk assessment in chemic...

abstract using tobit model, this study investigated factors affecting on crop risk frequency of farmers in the north khorasan province. data was collected through interviewing 120 farmers of north khorasan province in 2008. results showed that age, farm ownership and off farm employment affected frequency of risk negatively. non-agricultural activity, participating in a crop supervisory plan an...

Risks are natural and inherent characteristics of major projects. Risks are usually considered independently in analysis of risk responses. However, most risks are dependent on each other and dependent risks are rare in the real world. This paper proposes a model for proper risk response selection from the responses portfolio with the purpose of optimization of defined criteria for projects. Th...

the incidence of brain neoplasm has been progressively increasing in recent years in the industrialized countries. one of the reasons for this increased incidence could be better access to health care and improved diagnosis in the industrialized countries. it also appears that caucasians have a higher incidence than blacks or hispanics or asians. a number of risk factors have been identified an...

investors use different approaches to select optimal portfolio. so, optimal investment choices according to return can be interpreted in different models. the traditional approach to allocate portfolio selection called a mean - variance explains. another approach is markov chain. markov chain is a random process without memory. this means that the conditional probability distribution of the nex...

fault tree analysis (fta) as a probabilistic risk assessment (pra) method is used to identify basic causes leading to an undesired event, to represent logical relation of these basic causes in leading to the event, and finally to calculate the probability of occurrence of this event. to conduct a quantitative fta, one needs a fault tree along with failure data of the basic events (bes). someti...

risks mean cases of uncertainty of project, the impact of which is realized as a threat (negative aspect) and/or opportunity (positive aspect). the traditional viewpoint on risk is a negative viewpoint that implies damages, loss and harmful consequences. judgments such as this on risk merely emphasize on risks management and pay less attention to opportunities management. it is clear that some ...

selecting an effective project plan is a significant area in the project management. the present paper introduces a technique to identify the project plan efficient frontier for assessing the alternative project plans and selecting the best plan. the efficient frontier includes two criteria: the project cost and the project time. besides, the paper presents a scheme to incorporate directed acyc...