Ageing PSA incorporating effectiveness of maintenance and testing

This paper proposes a new approach to Ageing Probabilistic Safety Assessment (APSA) modelling, which is intended to be used to support risk-informed decisions on the effectiveness of maintenance management programs and technical specification requirements of critical equipment of Nuclear Power Plants (NPP) within the framework of the Risk Informed Decision Making according to R.G. 1.174 principles. This approach focuses on the incorporation of not only equipment ageing but also effectiveness of maintenance and efficiency of surveillance testing explicitly into APSA models and data. An example of application is presented, which centres on a critical safety-related equipment of a NPP in order to evaluate the risk impact of considering different approaches to APSA and the combined effect of equipment ageing and maintenance and testing alternatives along NPP design life. The risk impact of the several alternatives is quantified and the results shows that such risk depends largely on the model parameters, such as ageing factor, maintenance effectiveness, test efficiency.Authors are grateful to the Spanish Ministry of Science and Innovation for the financial support of this work (Research Project ENE2013-45540-R) and the Doctoral Fellow (BES-2011-043906).Martón Lluch, I.; Sánchez Galdón, AI.; Martorell Alsina, SS. (2015). Ageing PSA incorporating effectiveness of maintenance and testing. Reliability Engineering and System Safety. 139:131-140. https://doi.org/10.1016/j.ress.2015.03.022S13114013

Influence of morning maternal care on the behavioural responses of 8-week-old Beagle puppies to new environmental and social stimuli

In mammals, maternal care represents a major constituent of the early-life environment and its influence on individual development has been documented in rodents, non-human primates, humans and recently in adult dogs. The quality and quantity of mother-offspring interactions exerts a multilevel regulation upon the physiological, cognitive, and behavioural development of the offspring. For example, in rats variations in maternal behaviour, such as mother-pup body contact and the amount of licking towards pups in the nest during the early days after parturition, influences the endocrine, emotional, and behavioural responses to stress in the offspring. This produces long-term consequences, which may remain into adulthood and can be transmitted to subsequent generations. Literature about maternal care in dogs and its effect on puppy behaviour is still scarce, although the topic is receiving a growing interest. The aim of the present study was to determine the effects of morning maternal care on behavioural responses of puppies to new environmental and social stimuli. In order to achieve this, maternal care (licking, ano-genital licking, nursing and mother-puppy contact) was assessed in eight litters of domestic dogs living in standard rearing conditions during the first three weeks post-partum. Puppies were subjected to two behavioural tests (arena and isolation tests) at 58-60 days of age, and their behavioural responses were video recorded and analysed. Data was analysed using multivariate analyses (PCA, PLS).During the isolation test, a higher level of maternal care was associated with more exploration and a higher latency to emit the first yelp; on the contrary, a lower level of maternal care was associated with increased locomotion, distress vocalisations and destructive behaviours directed at the enclosure.These results, comparable to those reported in laboratory rat models and to some extent to those recently reported in dog literature, highlight the importance of maternal care on the behavioural development of domestic dog puppies

Inconsistent MHC class II association in Beagles experimentally infected with Leishmania infantum

The clinical outcome of Leishmania infantum infection in dogs varies from subclinical infection to severe disease. Researchers attribute this variability in clinical manifestations to the ability of the immune response to limit pathogen multiplication and dissemination, which is, in part, likely determined by the immune response genes. The aim of this study was to test the hypothesis that MHC class II genes are associated with disease outcome of experimental L. infantum infection in Beagles. Dog leukocyte antigen (DLA) class II haplotypes were characterised by sequence-based typing of Beagle dogs experimentally infected with L. infantum during vaccine challenge studies. Variability of response to infection was determined by clinical score, serology and quantification of L. infantum DNA in the bone marrow over the study period. Dogs showed limited DLA diversity and the DLA profiles of dogs recruited for the different vaccine challenge studies differed. There were variable responses to infection, despite the apparent restriction in genetic diversity. One haplotype DLA-DRB1*001:02–DQA1*001:01–DQB1*002:01 was associated with increased anti-Leishmania antibodies in one infection model, but no DLA associations were found in other groups or with parasite load or clinical score. Examination of this particular DLA haplotype in a larger number of dogs is required to confirm whether an association exists with the immune or clinical responses to L. infantum infection

Air radon concentration decrease in a waste water treatment plant

Rn-222 is a naturally occurring gas created from the decay of Ra-226. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiologica1 Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m(-3)). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2 h d(-1) (considering a maximum permissible dose of 20 mSv y(-1) averaged over 5 y) to 7 h d(-1).Juste Vidal, BJ.; Ortiz Moragón, J.; Verdú Martín, GJ.; Martorell Alsina, SS. (2015). Air radon concentration decrease in a waste water treatment plant. Oxford University Press. doi:10.1093/RPD/NCV329

Model to study the effect of workforce on a safety equipment and its optimization

Many industrial sectors are concerned on developing optimal maintenance planning because of the importance of maintenance on the economy and safety. Traditionally, the maintenance planning is formulated in terms of a multi-objective optimization problem where reliability, availability, maintainability and cost act as decision criteria and surveillance tests and maintenance strategies act as decision variables. However, the appropriate development of each maintenance strategy depends not only on the maintenance intervals but also on the resources available to implement such strategies. To solve the multi-objective optimization problem Particle Swarm Optimization (PSO) can be used. PSO is a stochastic global optimization technique inspired by social behavior of bird flocking or fish schooling. In this paper the multi-objective optimization of the maintenance of a nuclear power plant safety equipment using PSO is presented. (C) 2011 Published by Elsevier LtdCarlos Alberola, S.; Sánchez Galdón, AI.; Martorell Alsina, SS. (2011). Model to study the effect of workforce on a safety equipment and its optimization. Mathematical and Computer Modelling. 54(7-8):1808-1812. doi:10.1016/j.mcm.2011.01.015S18081812547-

An approach to address probabilistic assumptions on the availability of safety systems for deterministic safety analysis

[EN] There is an attempt nowadays to provide a more comprehensive and realistic safety assessment of design and operation of Nuclear Power Plants. In this context, innovative approaches are being proposed for safety assessment of nuclear power plants design including both design basis conditions and design extension conditions. An area of research aims at developing methods for combining insights from probabilistic and deterministic safety analyses in Option 4, also called realistic approach, from the International Atomic Energy Agency specific safety guide. The development of Option 4 or realistic approach involves the adoption of best estimate computer codes, best estimate assumptions on systems availability and best estimate of initial and boundary conditions for the safety analysis. This paper focusses on providing the fundamentals and practical implementation of an approach to integrate PSA-based probabilistic models and data, which incorporate best estimate assumptions on the availability of safety systems, into Option 4. It is presented a practical approach to identify relevant, i.e. most probable, configurations of safety systems and to assess the associated occurrence probability of each configuration using PSA models and data of a NPP, which is based on the use of a Pure Monte Carlo method. An example of application is provided to demonstrate how this approach performs. The case study focusses on an accident scenario corresponding to the initiating event Loss Of Feed Water (LOFW) for a typical three-loops Pressurized Water Reactor (PWR) NPP.Authors are grateful to the Spanish CSN (Consejo de Seguridad Nuclear) for the financial support of this research (Research Project SIN/4078/2013/640; MASA Project).Martorell Alsina, SS.; Martorell-Aygues, P.; Martón Lluch, I.; Sánchez Galdón, AI.; Carlos Alberola, S. (2017). An approach to address probabilistic assumptions on the availability of safety systems for deterministic safety analysis. Reliability Engineering & System Safety. 160:136-150. https://doi.org/10.1016/j.ress.2016.12.009S13615016

Memory effects induced by initial switching conditions

Initial-switching refers to the way in which the decay of an initially confined state begins, as the barrier isolating it from the exterior is relaxed. We study these effects in the context of Longhi's version of the Fano-Anderson model. Most authors assume the sudden approximation where the coupling is turned on instantaneously. We consider a finite rise time T, both numerically and analytically. When the coupling is ramped up linearly over a switching time T, we show that the asymptotic survival amplitude acquires a phase T and is modulated by a factor (sin T)/T. Several other results relating to the solution of the model are obtained. All site amplitudes have the same decay constant during the exponential decay regime. In the asymptotic regime, the amplitude and phase of decay oscillations depend on the initial-switching profile, but the period does not.Comment: 12 pages, 10 figures, accepted by Phys. Rev.

Cerclajes y enclavado intramedular en fracturas subtrocantéreas: ¿vascularización femoral o reducción anatómica?

Nuestro objetivo es valorar el beneficio y los resultados clínico-radiológicos del uso de los cerclajes y el enclavado intramedular en las fracturas subtrocantéreas tipo IIIA de Seinsheimer y compararlo con un grupo control. Se utilizaron dos grupos de 19 pacientes (grupo con cerclaje y grupo sin cerclaje) y se obtuvieron los siguientes resultados; tasas de reducción anatómica 89.5% y 84.2%; tasas de consolidación 100% y 94,7%; tiempo medio de consolidación 20 y 23.9 semanas. Los resultados utilizando la escala de Harris fueron de 62,7 y 68,3; y una tasa de complicaciones del 5.2% y del 21%. Estos resultados sugieren que el uso de cerclajes en las fracturas subtrocantéreas, no influencia de forma negativa nuestra tasa de consolidación, infección o complicaciones; sin embargo promovemos el uso de cerclajes después de intentar la reducción de manera cerrada, y siempre con un buen manejo de partes blandas.Our goal is to assess the benefit and the clinical and radiological outcomes of using cerclage and intramedullary nail in subtrochanteric fractures type IIIA of Seinsheimer and comparing with a control group. Two groups of 19 patients (cerclage group and non-cerclage group) were used and the following results were obtained; anatomic reduction rates 89.5% and 84.2; consolidation rates 100% and 94.7%; mean healing time 20 and 23.9 weeks. Our mean Harris Hip Score were 62.7 and 68.3; and a complication rate of 5.2% and 21%. The results suggest that the use of cerclage in subtrochanteric fractures does not negatively influence in the rate of consolidation, infection or complications as opposed to a subotpimal reduction. Nevertheless we emphasize open reduction and cerclage wiring after the attempt of closed reduction, and always taking care of soft tissues

Pattern Recognition Analysis of MR Spectra

The need for multivariate analysis of magnetic resonance spectroscopy (MRS) data was recognized about 20 years ago, when it became evident that spectral patterns were characteristic of some diseases. Despite this, there is no generally accepted methodology for performing pattern recognition (PR) analysis of MRS data sets. Here, the data acquisition and processing requirements for performing successful PR as applied to human MRS studies are introduced, and the main techniques for feature selection, extraction, and classification are described. These include methods of dimensionality reduction such as principal component analysis (PCA), independent component analysis (ICA), non-negative matrix factorization (NMF), and feature selection. Supervised methods such as linear discriminant analysis (LDA), logistic regression (LogR), and nonlinear classification are discussed separately from unsupervised and semisupervised classification techniques, including k –means clustering. Methods for testing and metrics for gauging the performance of PR models (sensitivity and specificity, the ‘Confusion Matrix’, ‘k –fold cross-validation’, ‘Leave One Out’, ‘Bootstrapping’, the ‘Receiver Operating Characteristic curve’, and balanced error and accuracy rates) are briefly described. This article ends with a summary of the main lessons learned from PR applied to MRS to date

Rotura bilateral de tendón cuadricipital asociado a tratamiento con atorvastatina.

La rotura del tendón del cuádriceps es una lesión relativamente poco frecuente. Puede asociarse a enfermedades sistémicas, trasplante renal, tratamientos crónicos u ocurrir de forma espontánea. Presentamos un caso de rotura bilateral de cuádriceps asociada a tratamiento crónico con atorvastatina.Quadriceps tendon rupture is a relatively rare lesion. It has been associated with chronic systemic diseases, renal transplantation or it may occur spontaneously. We present a case of bilateral quadriceps tendon rupture associated with chronic atorvastatin treatment