BACKGROUND Sampling from a large cohort in order to derive a subsample that would be sufficient for statistical analysis is a frequently used method for handling large data sets in epidemiological studies with limited resources for exposure measurement. For clinical studies however, when interest is in the influence of a potential risk factor, cohort studies are often the first choice with all ...

Background/Aims: Proton pump inhibitors (PPIs) are widely used to treat several acid-related gastrointestinal disorders. This study aimed investigate the risk of dementia in patients taking PPIs.Materials and Methods: A systematic review was conducted evaluate correlation between PPIs dementia. The methodological quality included studies evaluated using Risk Bias Assessment tool for non-randomi...

In this paper, we present an open and safe nested transaction model. We discuss the concurrency control and recovery algorithms for our model. Our nested transaction model uses the notion of a recovery point subtransaction in the nested transaction tree. It incorporates a prewrite operation before each write operation to increase the potential concurrency. Our transaction model is termed ``open...