A growing number of X-ray sources based on the free-electron laser (XFEL) principle are presently under construction or have recently started operation. The intense, ultrashort pulses of these sources will enable new insights in many different fields of science. A key problem is to provide x-ray optical elements capable of collecting the largest possible fraction of the radiation and to focus i...

Although a number of quantitative risk management measures and methods have been developed, the risk decision-making behaviour of construction project managers still needs to be further considered. Taking the characteristics of construction projects into consideration, this research put forward an integrated framework from the perspective of construction project managers and proposes 11 general...

background: several studies have demonstrated an increased risk of congenital hypothyroidism (ch) in girls in comparison to boys. objectives: the aim of this study was to determine the potential interactions that are able to change the effect of gender on congenital hypothyroidism. patients and methods: we conducted a matched 1:4 case-control study in hamadan province, western of iran, from 200...

We are interested in estimating the average effect of a binary treatment on a scalar outcome. If assignment to the treatment is exogenous or unconfounded, that is, independent of the potential outcomes given covariates, biases associated with simple treatment-control average comparisons can be removed by adjusting for differences in the covariates. Rosenbaum and Rubin (1983) show that adjusting...

Hepatic resection (HR) and liver transplantation (LT) are surgical treatment options for hepatocellular carcinoma (HCC). However, it is clinically impossible to perform a randomized, controlled study to determine the usefulness of these treatments. The present study compared survival rates and recurrence rates of HR versus living donor LT (LDLT) for HCC by using the propensity score method. Bet...

Young drivers are over-represented in road injury statistics, partly because they engage in more risky driving than older people. Although it is assumed that younger people have greater risk-propensity, defined as a positive attitude to risk, relevant theory is imprecise and relevant research is clouded by inappropriate measures. 89 participants aged 16-25 and 110 participants aged over 35 were...

In observational studies, investigators usually do not have the same control over the treatment assignment as they do with randomized controlled studies. As a result, the treatment and control groups may have a large difference on their observed covariates. These differences could lead to bias in estimating treatment effects. There are several propensity score based methods that could reduce th...

The Effect of Breastfeeding on Children’s Cognitive and Noncognitive Development This paper uses propensity score matching methods to investigate the relationship between breastfeeding and children’s cognitive and noncognitive development. We find that breastfeeding for four weeks is positively and statistically significantly associated with higher cognitive test scores, by around one tenth of ...

The aim is to assess the effect of imprisonment on rape myth acceptance. The research used a sample of male prisoners incarcerated for non-sexual crimes (n = 98) and a sample of males drawn from the general population (n = 160). Simple linear regression did not indicate a significant effect of incarceration on rape myth acceptance. After controlling for background covariates using propensity sc...