The Barker proposal: Combining robustness and efficiency in gradient-based MCMC.

There is a tension between robustness and efficiency when designing Markov chain Monte Carlo (MCMC) sampling algorithms. Here we focus on robustness with respect to tuning parameters, showing that more sophisticated algorithms tend to be more sensitive to the choice of step-size parameter and less robust to heterogeneity of the distribution of interest. We characterise this phenomenon by studying the behaviour of spectral gaps as an increasingly poor step-size is chosen for the algorithm.

Role of preoperative serum creatinine and estimated glomerular filtration rate values in asymptomatic patients undergoing carotid endarterectomy.

Background: The aim of this study was to evaluate the effect of chronic kidney disease (CKD), assessed by preoperative estimated glomerular filtration rate (eGFR) and serum creatinine (Cr), on postoperative outcomes and long-term survival in asymptomatic patients undergoing carotid endarterectomy (CEA).

Methods: We examined data about patients that underwent CEA between January 2002 and September 2014 in our Institution. Retrospective analysis to assess preoperative comorbidities and postoperative complications was performed.