A fuzzy expectation maximization based method for estimating the parameters of a multi-state degradation model from imprecise maintenance outcomes

Multi-State (MS) reliability models are used in practice to describe the evolution of degradation in industrial components and systems. To estimate the MS model parameters, we propose a method based on the Fuzzy Expectation-Maximization (FEM) algorithm, which integrates the evidence of the field inspection outcomes with information taken from the maintenance operators about the transition times from one state to another. Possibility distributions are used to describe the imprecision in the expert statements. A procedure for estimating the Remaining Useful Life (RUL) based on the MS model and conditional on such imprecise evidence is, then, developed. The proposed method is applied to a case study concerning the degradation of pipe welds in the coolant system of a Nuclear Power Plant (NPP). The obtained results show that the combination of field data with expert knowledge can allow reducing the uncertainty in degradation estimation and RUL prediction

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread wheat.

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread whea

Complete characterization of convergence to equilibrium for an inelastic Kac model

Pulvirenti and Toscani introduced an equation which extends the Kac caricature of a Maxwellian gas to inelastic particles. We show that the probability distribution, solution of the relative Cauchy problem, converges weakly to a probability distribution if and only if the symmetrized initial distribution belongs to the standard domain of attraction of a symmetric stable law, whose index $\alpha$ is determined by the so-called degree of inelasticity, $p>0$, of the particles: $\alpha=\frac{2}{1+p}$. This result is then used: (1) To state that the class of all stationary solutions coincides with that of all symmetric stable laws with index $\alpha$. (2) To determine the solution of a well-known stochastic functional equation in the absence of extra-conditions usually adopted

Molecular identification of the tropical seagrass Halophila stipulacea from Turkey

Halophila stipulacea (Forsskål) Ascherson, a tropical seagrass, is thought to be a Lessepsian immigrant that entered the Mediterranean Sea from the Red Sea after the opening of the Suez Canal (1869). Up to date, no genetic studies of H. stipulacea from Turkey are available. In order to verify the molecular identity of Turkish isolates of H. stipulacea, a part of the rDNA ITS region was sequenced. Comparisons of the genetic polymorphism of this region between isolates from the Turkish coasts of the Aegean Sea and individuals from putative native (Red Sea) and introduced (Mediterranean) populations deposited previously in GenBank were performed. No intra-individual variability was found in the region considered among the isolates from Turkey

The reliability of the general functioning scale in Norwegian 13–15-year-old adolescents and association with family dinner frequency

Background Family environment is crucial to the development of health behaviors into adolescence and adulthood. The aims of this study were (1) to explore the reliability of the General Functioning Scale (GFS) among Norwegian 13-15-year-olds, and (2) to assess whether family functioning reported by adolescents was associated with family dinner frequency. Methods In total 440 secondary-school students were invited to participate in this cross-sectional web-based questionnaire survey, with 54 participating in the test-retest study. Test-retest and internal consistency were assessed for the 12-item GFS-scale. Associations between family functioning and family dinner frequency were tested using multiple logistic regression. Results The GFS had high internal consistency (corrected item-total correlations ranging from 0.40 to 0.65, Cronbach’s α = 0.85), and excellent test–retest reliability (intra-class correlation coefficient = 0.83). In the logistic regression model, a higher score on GFS (poorer family functioning) was associated with a reduced likelihood of having dinner together on a daily basis (i.e., 6–7 times per week, OR = 0.36, CI = 0.20–0-64) after adjusting for age, gender, ethnicity, living situation and parental education level. Conclusions The GFS had high reliability. As poorer family functioning was associated with less frequent family dinners, the family environment may be an important (contextual) target to influence adolescent health behaviors. It would be of interest to further explore the role of family functioning in relation to adolescents’ dietary habits, besides shared family meals, and to reveal the mechanisms underlying such relationships.publishedVersio

Evolution and diversification within the intertidal brown macroalgae Fucus spiralis/F. vesiculosus species complex in the North Atlantic

We examined 733 individuals of Fucusspiralis from 21 locations and 1093 Fucusvesiculosus individuals from 37 locations throughout their northern hemisphere ranges using nuclear and mitochondrial markers. Three genetic entities of F. spiralis were recovered. In northern and sympatric populations, the presence of "F. spiralis Low" in the mid-intertidal and "F. spiralis High" in the high-intertidal was confirmed and both co-occurred with the sister species F. vesiculosus. The third and newly-discovered entity, "F. spiralis South", was present mainly in the southern range, where it did not co-occur with F. vesiculosus. The South entity diverged early in allopatry, then hybridized with F. vesiculosus in sympatry to produce F. spiralis Low. Ongoing parallel evolution of F. spiralis Low and F. spiralis High is most likely due to habitat preference/local selection and maintained by preferentially selfing reproductive strategies. Contemporary populations of F. spiralis throughout the North Atlantic stem from a glacial refugium around Brittany involving F. spiralis High; F. spiralis South was probably unaffected by glacial episodes. Exponential population expansion for F. vesiculosus began during the Cromer and/Holstein interglacial period (300,000-200,000 yrs BP). Following the last glacial maximum (30,000-22,000 yrs BP), a single mtDNA haplotype from a glacial refugium in SW Ireland colonized Scandinavia, the Central Atlantic islands, and the W Atlantic