Vulnerability models for environmental risk assessment. Application to a nuclear power plant containment building

Environmental risk management consists of making decisions on human activities or construction designs that are affected by the environment and/or have consequences or impacts on it. In these cases, decisions are made such that risk is minimized. In this regard, the forthcoming paper develops a close form that relates risk with cost, hazard, and vulnerability; and then focuses on vulnerability. The vulnerability of a system under an external action can be described by the conditional probability of the degrees of damage after an event. This vulnerability model can be obtained by a simplicial regression of those outputs, as a response variable, on explanatory variables. After a theoretical explanation, the authors present the case study of a nuclear power plant containment building. Once a given overpressure is registered inside the containment building, three possible outputs are to be considered: serviceability, breakdown, and collapse. The study consists of three steps: (a) modelling the containment building using the finite element method; (b) given an overpressure, simulating uncertain parameters related to material constitutive equations in order to obtain the corresponding proportions; (c) performing a simplicial regression to obtain a meaningful vulnerability model. The simulation provides normalized-to-unity outputs under the overpressure conditions. The obtained vulnerability model is in definite correspondence with previous results in nuclear power plant safety analysis reports.Spain. Ministerio de Educación, Cultura y Deporte (BOE n. 190, August 9th, 2012) to collaborate with the Department of Applied Mathematics III at UPC-BarcelonaTech from September 2012 to June 2013)Spain. Ministerio de Ciencia y Tecnología (project ‘Ingenio Mathematica (i-MATH)’ (Ref. No. CSD2006-00032))Spain. Ministerio de Ciencia y Tecnología (project ‘CODARSS’ (Ref. MTM2009-13272))Spain. Ministerio de Economía y Competitividad (project ‘METRICS’ (Ref. MTM2012- 33236))Catalonia (Spain). Agencia de Gestio d'Ajuts Universitaris i de Recerca (project Ref. 2009SGR424

The effect of scale in daily precipitation hazard assessment

Daily precipitation is recorded as the total amount of water collected by a rain-gauge in 24 h. Events are modelled as a Poisson process and the 24 h precipitation by a Generalised Pareto Distribution (GPD) of excesses. Hazard assessment is complete when estimates of the Poisson rate and the distribution parameters, together with a measure of their uncertainty, are obtained. The shape parameter of the GPD determines the support of the variable: Weibull domain of attraction (DA) corresponds to finite support variables as should be for natural phenomena. However, Fréchet DA has been reported for daily precipitation, which implies an infinite support and a heavy-tailed distribution. Bayesian techniques are used to estimate the parameters. The approach is illustrated with precipitation data from the Eastern coast of the Iberian Peninsula affected by severe convective precipitation. The estimated GPD is mainly in the Fréchet DA, something incompatible with the common sense assumption of that precipitation is a bounded phenomenon. The bounded character of precipitation is then taken as a priori hypothesis. Consistency of this hypothesis with the data is checked in two cases: using the raw-data (in mm) and using log-transformed data. As expected, a Bayesian model checking clearly rejects the model in the raw-data case. However, log-transformed data seem to be consistent with the model. This fact may be due to the adequacy of the log-scale to represent positive measurements for which differences are better relative than absolute

Microbiome datasets are compositional: and this is not optional

Datasets collected by high-throughput sequencing (HTS) of 16S rRNA gene amplimers, metagenomes or metatranscriptomes are commonplace and being used to study human disease states, ecological differences between sites, and the built environment. There is increasing awareness that microbiome datasets generated by HTS are compositional because they have an arbitrary total imposed by the instrument. However, many investigators are either unaware of this or assume specific properties of the compositional data. The purpose of this review is to alert investigators to the dangers inherent in ignoring the compositional nature of the data, and point out that HTS datasets derived from microbiome studies can and should be treated as compositions at all stages of analysis. We briefly introduce compositional data, illustrate the pathologies that occur when compositional data are analyzed inappropriately, and finally give guidance and point to resources and examples for the analysis of microbiome datasets using compositional data analysis.Peer ReviewedPostprint (published version

Cytogenetic sensitivity of three Fanconi anemia heterozygotes to bleomycin and ionizing radiation

It is well known that Fanconi anemia (FA) patients show a hypersensitivity to the effect of cross-linking agents such as mitomycin C and diepoxybutane, while the sensitivity of these patients to ionizing radiation is controversial. Fanconi anemia heterozygotes do not show a hypersensitivity to the above-mentioned agents. However, bleomycin it is used to identify mutagen sensitive individuals, especially among head and neck cancer patients. We present here a preliminary study in which the mean frequencies of bleomycin-induced chromatid breaks (ctb) from three FA heterozygotes (X = 0.90, range 0.80-1.01) and 11 controls (X = 0.40, range 0.21-0.66) differ significantly (P<.001), indicating a high sensitivity to bleomycin of G2 lymphocytes from these three FA heterozygotes. An increased sensitivity was not observed after exposure of G0 lymphocytes to 2 Gy of ionizing radiation

Morfologia i formació del complexe sinaptinèmic a espermatòcits i oòcits de Mus musculus

A method for the sequential study of synaptonemal complexes by light and electron microscopy has been used to characterize the synaptic process in mouse (Mus musculus) spermatocytes and oocytes. Pre- and post-synaptic figures can be easily identified

Comparison of X-ray dose-response curves obtained by chromosome painting using conventional and PAINT nomenclatures

Altres ajuts: Consejo Español de Seguridad Nuclear (exp. 246/96)Purpose: The compare the suitability of PAINT and conventional nomenclature systems for the construction of chromosome aberration dose- effect curves for X-rays using FISH techniques, and to compare these curves with those based on solid-stained dicentrics analysed in first division metaphases by the FPG technique. Materials and methods: Blood samples were irradiated at 0.1, 0.25, 0.50, 0.75, 1, 1.5, 2, 3, 4 and 5 Gy 180 kV X-rays. FISH painting was performed using probes for chromosomes 1, 4 and 11 in combination with a pan-centromeric probe. Results: Translocations showed a higher background frequency than dicentrics. This influences the ratio of translocations:dicentrics at the lower doses and the uncertainties of dose- effect curves for translocations. The dose-effect curves for dicentrics obtained by FISH and solid stain were in close agreement. Conclusion: For short-term biological dosimetry purposes by FISH, the use of dic(BA) (PAINT nomenclature) or total dicentrics (conventional nomenclature) should give similar dose estimates. For dose reconstruction, the use of total or complete translocations result in similar uncertainties

Balances: a new perspective for microbiome analysis

High-throughput sequencing technologies have revolutionized microbiome research by allowing the relative quantification of microbiome composition and function in different environments. In this work we focus on the identification of microbial signatures, groups of microbial taxa that are predictive of a phenotype of interest. We do this by acknowledging the compositional nature of the microbiome and the fact that it carries relative information. Thus, instead of defining a microbial signature as a linear combination in real space corresponding to the abundances of a group of taxa, we consider microbial signatures given by the geometric means of data from two groups of taxa whose relative abundances, or balance, are associated with the response variable of interest. In this work we present selbal, a greedy stepwise algorithm for selection of balances or microbial signatures that preserves the principles of compositional data analysis. We illustrate the algorithm with 16S rRNA abundance data from a Crohn’s microbiome study and an HIV microbiome study. We propose a new algorithm for the identification of microbial signatures. These microbial signatures can be used for diagnosis, prognosis, or prediction of therapeutic response based on an individual’s specific microbiota.Peer ReviewedPostprint (published version

Cytogenetic effects of irradiation on somatic and germ cells

This paper summarizes the results obtained in two of the research projects carried out in our laboratory within the radiation protection programs of the Consejo de Seguridad Nuclear and the European Union. These two research lines are fundamentally interconnected, since the analysis of the cytogenetic effects of radiation on somatic cells studies the consequences of occupational or accidental exposure to radiation for the individual, especially from the point of view of developing some type of malignancy, while the studies carried out in germ cells evaluate the risk of exposure for future generations, through the transmission of chromosome abnormalities via affected spermatozoa. In both cases these studies, which were mainly carried out during the last six years, in addition to providing basic data for the assessment of the consequences of radiation exposure and defining the steps to be taken to prevent the transmission of chromosome anomalies to the offspring in cases of therapeutic exposure, have also been fundamental in developing more effective techniques for the evaluation of the cytogenetic consequences of exposure to radiation