Investigating prior parameter distributions in the inverse modelling of water distribution hydraulic models

PublishedJournal Article© 2014 Journal of Mechanical Engineering. All rights reserved. Inverse modelling concentrates on estimating water distribution system (WDS) model parameters that are not directly measurable, e.g. pipe roughness coefficients, which can, therefore, only be estimated by indirect approaches, i.e. inverse modelling. Estimation of the parameter and predictive uncertainty of WDS models is an essential part of the inverse modelling process. Recently, Markov Chain Monte Carlo (MCMC) simulations have gained in popularity in uncertainty analyses due to their effective and efficient exploration of posterior parameter probability density functions (pdf). A Bayesian framework is used to infer prior parameter information via a likelihood function to plausible ranges of posterior parameter pdf. Improved parameter and predictive uncertainty are achieved through the incorporation of prior pdf of parameter values and the use of a generalized likelihood function. We used three prior information sampling schemes to infer the pipe roughness coefficients of WDS models. A hypothetical case study and a real-world WDS case study were used to illustrate the strengths and weaknesses of a particular selection of a prior information pdf. The results obtained show that the level of parameter identifiability (i.e. sensitivity) is an important property for prior pdf selection.We are obliged to Jasper A. Vrugt and Cajo ter Braak for providing the code of the DREAM(ZS) algorithm and graphical post-processing software

Influence of socioeconomic factors on pregnancy outcome in women with structural heart disease

OBJECTIVE: Cardiac disease is the leading cause of indirect maternal mortality. The aim of this study was to analyse to what extent socioeconomic factors influence the outcome of pregnancy in women with heart disease.  METHODS: The Registry of Pregnancy and Cardiac disease is a global prospective registry. For this analysis, countries that enrolled ≥10 patients were included. A combined cardiac endpoint included maternal cardiac death, arrhythmia requiring treatment, heart failure, thromboembolic event, aortic dissection, endocarditis, acute coronary syndrome, hospitalisation for cardiac reason or intervention. Associations between patient characteristics, country characteristics (income inequality expressed as Gini coefficient, health expenditure, schooling, gross domestic product, birth rate and hospital beds) and cardiac endpoints were checked in a three-level model (patient-centre-country).  RESULTS: A total of 30 countries enrolled 2924 patients from 89 centres. At least one endpoint occurred in 645 women (22.1%). Maternal age, New York Heart Association classification and modified WHO risk classification were associated with the combined endpoint and explained 37% of variance in outcome. Gini coefficient and country-specific birth rate explained an additional 4%. There were large differences between the individual countries, but the need for multilevel modelling to account for these differences disappeared after adjustment for patient characteristics, Gini and country-specific birth rate.  CONCLUSION: While there are definite interregional differences in pregnancy outcome in women with cardiac disease, these differences seem to be mainly driven by individual patient characteristics. Adjustment for country characteristics refined the results to a limited extent, but maternal condition seems to be the main determinant of outcome

Refined timing of porphyry copper formation in the Serbian and Bulgarian portions of the Cretaceous Carpatho-Balkan belt

International audiencehe Bor district in Serbia and the Panagyurishte district in Bulgaria are part of the mineralized Late Cretaceous Carpatho-Balkan igneous belt. 40Ar/39Ar laser probe radiometric age information from porphyry copper deposits of the two districts in this study provides new constraints on the timing of host-rock emplacement and the hydrothermal alteration that is linked to the porphyry mineralization. In the Bor district, igneous hornblende from the host intrusions has an average plateau age at 84.0 ± 1.5 Ma (2σ). The timing of alteration is constrained by white mica with an average inverse isochron age of 85.4 ± 1.8 Ma and an average plateau age at 86.6 ± 1.0 Ma (elevated by a small excess 40Ar contribution). Together, these analyses indicate that porphyry mineralization occurred around 85 Ma. In the Panagyurishte district previous isotopic studies have produced much older host-rock ages in the northwest than mineralization ages in the southeast. Ages of igneous and alteration mineral separates from Elatsite and Medet in the northwestern and central parts of the district from the present study confirm pluton emplacement at 90.8 ± 0.8 Ma but much younger alteration at 79.5 ± 0.5 Ma. It is proposed that two episodes of magmatic-hydrothermal activity have affected the district, one at ~91 Ma, with the emplacement of the majority of the plutonic rocks, and one at 79 to 80 Ma during which the alteration micas were reset. Integration of these new ages with existing radiometric age information emphasizes the complex history of magmatic-hydrothermal activity along the immature Late Cretaceous Carpatho-Balkan convergent margin

Odontogenic Cysts: Analysis of 680 Cases in Brazil

The purpose of this study was to evaluate the prevalence of 680 odontogenic cysts diagnosed in Porto Alegre, RS, Brazil, and to compare results with findings in the literature. Data of odontogenic cysts diagnosed from 1985 to 2005 were collected from the files of the Oral Pathology Laboratory of Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, RS, Brazil, and entered in a standardized form for later comparisons. The most prevalent odontogenic cysts were radicular (72.50%), dentigerous (22.20%) and residual (4.26%) cysts. The mandible of white patients was the anatomic site and ethnic group most frequently affected by this disease. Four of the six types of cysts were more frequent in the second and fourth decades of life, and no significant differences were found between sexes in the diagnosis of odontogenic cysts. In conclusion, the prevalence of odontogenic cysts was similar to that reported in the literature, which shows that inflammatory cysts are the most frequent