A review of dendrogeomorphological research applied to flood risk analysis in Spain

Over the last forty years, applying dendrogeomorphology to palaeoflood analysis has improved estimates of the frequency and magnitude of past floods worldwide. This paper reviews the main results obtained by applying dendrogeomorphology to flood research in several case studies in Central Spain. These dendrogeomorphological studies focused on the following topics: (1) anatomical analysis to understand the physiological response of trees to flood damage and improve sampling efficiency; (2) compiling robust flood chronologies in ungauged mountain streams, (3) determining flow depth and estimating flood discharge using two-dimensional hydraulic modelling, and comparing them with other palaeostage indicators; (4) calibrating hydraulic model parameters (i.e. Manning roughness); and (5) implementing stochastic-based, cost–benefit analysis to select optimal mitigation measures. The progress made in these areas is presented with suggestions for further research to improve the applicability of dendrogeochronology to palaeoflood studies. Further developments will include new methods for better identification of the causes of specific types of flood damage to trees (e.g. tilted trees) or stable isotope analysis of tree rings to identify the climatic conditions associated with periods of increasing flood magnitude or frequency.

More than just Good Luck. How to Explain the Success of Monte Carlo Simulations

Monte Carlo simulation is a powerful method in many natural and social sciences. But what sort of method is it? And where does its power come from? Are Monte Carlo simulations experiments, theories or something else? The aim of this talk is to answer these questions and to explain the power of Monte Carlo simulations. I provide a classification of Monte Carlo techniques and defend the claim that Monte Carlo simulation is a sort of inference.

Coronary artery disease in patients undergoing TAVI: why, what, when and how to treat.

Coronary artery disease (CAD) and aortic valve stenosis (AS) are frequently coexisting. It has been reported that CAD is present in 40% of patients with AS undergoing surgical aortic valve replacement, and in up to 60% of patients with AS undergoing transcatheter aortic valve implantation (TAVI). Elderly patients with CAD and AS are characterised by higher baseline risk profiles as compared to patients with isolated AS, increasing the complexity of their therapeutic management. In patients with CAD and AS the combination of coronary artery bypass grafting (CABG) and surgical aortic valve replacement has been shown to improve survival. Therefore, CABG is recommended in patients with CAD and AS undergoing surgical aortic valve replacement according to current guidelines of the European Society of Cardiology (ESC) and of the American College of Cardiology Foundation/American Heart Association (ACCF/AHA). Conversely, whether the presence of CAD has any prognostic implications in elderly patients with severe AS undergoing TAVI is still a matter of debate. Of note, according to the most recent ESC guidelines on myocardial revascularisation, percutaneous revascularisation should be considered in patients undergoing TAVI with a stenosis >70% in proximal coronary segments (class IIa, level of evidence C). The aim of this article is to provide an overview of evidence supporting the need for coronary revascularisation in patients with severe AS and CAD undergoing TAVI, and to summarise optimal timing and treatment modalities for percutaneous coronary interventions in these patients.

Clinical herniation – how to improve differentiation between WFNS grade IV and V

Objective: Current data show a favorable outcome after poor grade subarachnoid hemorrhage (SAH) in up to 50% of patients. This limits the use of the WFNS scale for drawing treatment decisions. We therefore analyzed how clinical signs of herniation might improve the existing WFNS grading. Therefore we compared the current WFNS grading and a modified WFNS grading with respect to outcome. Method: We performed a retrospective study including 182 poor grade SAH patients. Patients were graded according to the original WFNS scale and additionally into a modified classification the “WFNS herniation” (WFNSh grade IV: no herniation; grade V clinical signs of herniation). Outcome was compared between these two grading systems with respect to the dichotomized modified Rankin scale after 6 months. Results: The WFNS and WFNSh showed a positive predictive value (PPV) for poor outcome of 74.3% (OR 3.79, 95% confidence interval [CI]=1.94, 7.54) and 85.7% (OR 8.27, 95% CI=3.78, 19.47), respectively. With respect to mortality the PPV was 68.3% (OR 3.9, 95% CI=2.01, 7.69) for the WFNS grade V and 77.9% (OR 6.22, 95% CI=3.07, 13.14) for the WFNSh grade V. Conclusions: Using positive clinical signs of herniation instead of “no response to pain stimuli” (motor Glasgow Coma Scale Score) can improve WFNS V grading. Using this modification, prediction of poor outcome or death improves.