The main purpose of the study is determination of the pollutants hazard potential as well as environmental vulnerability of Qarah Su River. First the most significant pollutant sources in the Qarah Su river watershed were identified and then accordingly the pollution hazard potential rate was calculated in Universal Ranking System Model setting. Then, by generalizing the algebraic sum of the re...

background: the aim of this study is to evaluate the association between different treatments and survival time of breast cancer patients using either standard cox model or stratified cox model. methods: the study was conducted on 15830 women diagnosed with breast cancer in british columbia, canada.  they were divided into eight groups according to patients’ ages and stage of disease either cox...

BACKGROUND The Cox model has been the mainstay of survival analysis in the critically ill and time-dependent covariates have infrequently been incorporated into survival analysis. OBJECTIVES To model 28-day survival of patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), and compare the utility of Cox and accelerated failure time (AFT) models. METHODS Prospe...

In many countries, studies to determine the severity of desertification and providing land plans to implement desertification. One of the models is modified MEDALUS or Iranian model (IMDPA), has been used in present research in order to investigate desertification situation in the Tashk region of Fars province. In this research, the modified IMDPA model used with emphasis on the water, soil and...

In many countries, studies to determine the severity of desertification and providing land plans to implement desertification. One of the models is modified MEDALUS or Iranian model (IMDPA), has been used in present research in order to investigate desertification situation in the Tashk region of Fars province. In this research, the modified IMDPA model used with emphasis on the water, soil and...

This paper discusses the preservation of some stochastic orders between two interdependent series and parallel systems when the survival and distribution functions of all components switch to the exponentiated model. For the series systems, the likelihood ratio, hazard rate, usual, aging faster, aging intensity, convex transform, star, superadditive and dispersive orderings, and for the paralle...

Graphical methods based on the analysis of differences between log cumulative hazard functions are considered for a two-group semi-proportional hazard model which allows for interaction between treatments and covariates. Confidence procedures and test statistics that can be used to test for interaction and for main effects are developed. Their use is illustrated by applying them to the analysis...