rare failure events: Topics by WorldWideScience.org

Sample records for rare failure events

Rare event simulation using Monte Carlo methods

CERN Document Server

Rubino, Gerardo

2009-01-01

In a probabilistic model, a rare event is an event with a very small probability of occurrence. The forecasting of rare events is a formidable task but is important in many areas. For instance a catastrophic failure in a transport system or in a nuclear power plant, the failure of an information processing system in a bank, or in the communication network of a group of banks, leading to financial losses. Being able to evaluate the probability of rare events is therefore a critical issue. Monte Carlo Methods, the simulation of corresponding models, are used to analyze rare events. This book sets out to present the mathematical tools available for the efficient simulation of rare events. Importance sampling and splitting are presented along with an exposition of how to apply these tools to a variety of fields ranging from performance and dependability evaluation of complex systems, typically in computer science or in telecommunications, to chemical reaction analysis in biology or particle transport in physics. ...
Rare event techniques applied in the Rasmussen study

International Nuclear Information System (INIS)

Vesely, W.E.

1977-01-01

The Rasmussen Study estimated public risks from commercial nuclear power plant accidents, and therefore the statistics of rare events had to be treated. Two types of rare events were specifically handled, those rare events which were probabilistically rare events and those which were statistically rare events. Four techniques were used to estimate probabilities of rare events. These techniques were aggregating data samples, discretizing ''continuous'' events, extrapolating from minor to catastrophic severities, and decomposing events using event trees and fault trees. In aggregating or combining data the goal was to enlarge the data sample so that the rare event was no longer rare, i.e., so that the enlarged data sample contained one or more occurrences of the event of interest. This aggregation gave rise to random variable treatments of failure rates, occurrence frequencies, and other characteristics estimated from data. This random variable treatment can be interpreted as being comparable to an empirical Bayes technique or a Bayesian technique. In the discretizing event technique, events of a detailed nature were grouped together into a grosser event for purposes of analysis as well as for data collection. The treatment of data characteristics as random variables helped to account for the uncertainties arising from this discretizing. In the severity extrapolation technique a severity variable was associated with each event occurrence for the purpose of predicting probabilities of catastrophic occurrences. Tail behaviors of distributions therefore needed to be considered. Finally, event trees and fault trees were used to express accident occurrences and system failures in terms of more basic events for which data existed. Common mode failures and general dependencies therefore needed to be treated. 2 figures
Estimating the probability of rare events: addressing zero failure data.

Science.gov (United States)

Quigley, John; Revie, Matthew

2011-07-01

Traditional statistical procedures for estimating the probability of an event result in an estimate of zero when no events are realized. Alternative inferential procedures have been proposed for the situation where zero events have been realized but often these are ad hoc, relying on selecting methods dependent on the data that have been realized. Such data-dependent inference decisions violate fundamental statistical principles, resulting in estimation procedures whose benefits are difficult to assess. In this article, we propose estimating the probability of an event occurring through minimax inference on the probability that future samples of equal size realize no more events than that in the data on which the inference is based. Although motivated by inference on rare events, the method is not restricted to zero event data and closely approximates the maximum likelihood estimate (MLE) for nonzero data. The use of the minimax procedure provides a risk adverse inferential procedure where there are no events realized. A comparison is made with the MLE and regions of the underlying probability are identified where this approach is superior. Moreover, a comparison is made with three standard approaches to supporting inference where no event data are realized, which we argue are unduly pessimistic. We show that for situations of zero events the estimator can be simply approximated with 1/2.5n, where n is the number of trials. © 2011 Society for Risk Analysis.
Statistical trend analysis methodology for rare failures in changing technical systems

International Nuclear Information System (INIS)

Ott, K.O.; Hoffmann, H.J.

1983-07-01

A methodology for a statistical trend analysis (STA) in failure rates is presented. It applies primarily to relatively rare events in changing technologies or components. The formulation is more general and the assumptions are less restrictive than in a previously published version. Relations of the statistical analysis and probabilistic assessment (PRA) are discussed in terms of categorization of decisions for action following particular failure events. The significance of tentatively identified trends is explored. In addition to statistical tests for trend significance, a combination of STA and PRA results quantifying the trend complement is proposed. The STA approach is compared with other concepts for trend characterization. (orig.)
Rare events: a state of the art

International Nuclear Information System (INIS)

Uppuluri, V.R.R.

1980-12-01

The study of rare events has become increasingly important in the context of nuclear safety. Some philosophical considerations, such as the framework for the definition of a rare event, rare events and science, rare events and trans-science, and rare events and public perception, are discussed. The technical work of the Task Force on problems of Rare Events in the Reliability Analysis of Nuclear Plants (1976-1978), sponsored by OECD, is reviewed. Some recent technical considerations are discussed, and conclusions are drawn. The appendix contains an essay written by Anne E. Beachey, under the title: A Study of Rare Events - Problems and Promises
Organizational Learning in Rare Events

DEFF Research Database (Denmark)

Andersen, Kristina Vaarst; Tyler, Beverly; Beukel, Karin

When organizations encounter rare events they often find it challenging to extract learning from the experience. We analyze opportunities for organizational learning in one such rare event, namely Intellectual Property (IP) litigation, i.e., when organizations take disputes regarding their intell......When organizations encounter rare events they often find it challenging to extract learning from the experience. We analyze opportunities for organizational learning in one such rare event, namely Intellectual Property (IP) litigation, i.e., when organizations take disputes regarding...... the organization little discretion to utilize any learning from past litigation success. Thus, learning appears be to most beneficial in infringement cases. Based on statistical analysis of 10,211 litigation court cases in China, we find support for our hypotheses. Our findings suggest that organizations can learn...
Bayesian analysis of rare events

Energy Technology Data Exchange (ETDEWEB)

Straub, Daniel, E-mail: straub@tum.de; Papaioannou, Iason; Betz, Wolfgang

2016-06-01

In many areas of engineering and science there is an interest in predicting the probability of rare events, in particular in applications related to safety and security. Increasingly, such predictions are made through computer models of physical systems in an uncertainty quantification framework. Additionally, with advances in IT, monitoring and sensor technology, an increasing amount of data on the performance of the systems is collected. This data can be used to reduce uncertainty, improve the probability estimates and consequently enhance the management of rare events and associated risks. Bayesian analysis is the ideal method to include the data into the probabilistic model. It ensures a consistent probabilistic treatment of uncertainty, which is central in the prediction of rare events, where extrapolation from the domain of observation is common. We present a framework for performing Bayesian updating of rare event probabilities, termed BUS. It is based on a reinterpretation of the classical rejection-sampling approach to Bayesian analysis, which enables the use of established methods for estimating probabilities of rare events. By drawing upon these methods, the framework makes use of their computational efficiency. These methods include the First-Order Reliability Method (FORM), tailored importance sampling (IS) methods and Subset Simulation (SuS). In this contribution, we briefly review these methods in the context of the BUS framework and investigate their applicability to Bayesian analysis of rare events in different settings. We find that, for some applications, FORM can be highly efficient and is surprisingly accurate, enabling Bayesian analysis of rare events with just a few model evaluations. In a general setting, BUS implemented through IS and SuS is more robust and flexible.
Myxedema Coma with Reversible Cardiopulmonary Failure: a Rare Entity in 21St Century.

Science.gov (United States)

Dhakal, Prajwal; Pant, Manisha; Acharya, Pranab Sharma; Dahal, Sumit; Bhatt, Vijaya Raj

2015-09-01

Myxedema coma, a rare entity in 21st century in developed nations, is a decompensated phase of hypothyroidism with high mortality rates. We describe a young woman with myxedema, who developed respiratory failure, congestive heart failure and significant pericardial effusion, some of the uncommon manifestations. Decreased cardiac contractility can result in cardiomyopathy and heart failure. As illustrated by this case, myxedema can also result in significant pericardial effusion due to increased vascular permeability. Myxedema can further be complicated by alveolar hypoventilation and respiratory failure secondary to the lack of central drive as well as respiratory muscle weakness. Prompt therapy with thyroid hormone replacement, glucocorticoid therapy, aggressive supportive care and management of the precipitating event can save lives and reverse the cardiopulmonary symptoms, as in our patient. Hence, physicians should have a high index of suspicion for myxedema coma in patients with unexplained cardiopulmonary failure. Our report is, therefore, aimed at bringing awareness about the rare but fatal manifestations of myxedema coma.
Proceedings of the meeting of a task force on problems of rare events in the reliability analysis of nuclear power plants

International Nuclear Information System (INIS)

1976-01-01

In safety problems of nuclear plants interest centres on various types of rare events. These may extend from rare modes of failures in the component parts of the system and plant, the simultaneous occurrence of a very low resistance of a structural member and an extremely high load, to rare catastrophic failures which affect whole plant and system complexes. The obvious need is therefore to understand the patterns of behaviour of these events in space and time domains and be able to make some adequate estimate of their probability of occurrence. In 1975, a Task Force of Experts on the Statistical Analysis of Rare Events in Nuclear Installations was set up, its main objective being to explore methods for handling the problems of reliability analysis involving rare events. The main topic area of the Ispra meeting concerns the statistical analysis of structures such as containment and pressure vessels, automatic protection systems, and allied items, with a view to giving a quantified probabilistic statement on particular reliability characteristics. The particular subjects covered by the invited experts who would normally be working in specialized fields, includes, specifically, statistical modelling of rare events, decision theory applied to rare events, small sampling theory in the case of rare events. Man-made phenomena as well as natural phenomena are also considered, as they involve different approaches to modelling. 22 papers are presented, with reports on group discussions
Determinants of performance in rare strategic events

DEFF Research Database (Denmark)

Andersen, Kristina Vaarst; Beukel, Karin

The paper develops and tests a theoretical framework explaining how emotions and learning affect outcomes of rare strategic events, namely Intellectual Property litigations. We investigate how organizations? negative emotions influence performance outcome in IP litigations negatively. Though...... cumulative learning in rare strategic events is scarce, and cannot be understood through the standard framework of routines and capability development, we argue that firms may learn from rare events, and propose that learning moderates the negative effect of emotions. We test this utilizing data on all...... publically available IP litigation cases in China from 2001 to 2009 (n=13,030). We find that when organizations undergo emotional negative stress they lose IP litigations more often, but development of roadmaps though past successes moderate the negative effects from emotional distress....
Science-based risk assessments for rare events in a changing climate

Science.gov (United States)

Sobel, A. H.; Tippett, M. K.; Camargo, S. J.; Lee, C. Y.; Allen, J. T.

2014-12-01

History shows that substantial investments in protection against any specific type of natural disaster usually occur only after (usually shortly after) that specific type of disaster has happened in a given place. This is true even when it was well known before the event that there was a significant risk that it could occur. Presumably what psychologists Kahneman and Tversky have called "availability bias" is responsible, at least in part, for these failures to act on known but out-of-sample risks. While understandable, this human tendency prepares us poorly for events which are very rare (on the time scales of human lives) and even more poorly for a changing climate, as historical records become a poorer guide. A more forward-thinking and rational approach would require scientific risk assessments that can place meaningful probabilities on events that are rare enough to be absent from the historical record, and that can account for the influences of both anthropogenic climate change and low-frequency natural climate variability. The set of tools available for doing such risk assessments is still quite limited, particularly for some of the most extreme events such as tropical cyclones and tornadoes. We will briefly assess the state of the art for these events in particular, and describe some of our ongoing research to develop new tools for quantitative risk assessment using hybrids of statistical methods and physical understanding of the hazards.
Extreme Quantum Memory Advantage for Rare-Event Sampling

Science.gov (United States)

Aghamohammadi, Cina; Loomis, Samuel P.; Mahoney, John R.; Crutchfield, James P.

2018-02-01

We introduce a quantum algorithm for memory-efficient biased sampling of rare events generated by classical memoryful stochastic processes. Two efficiency metrics are used to compare quantum and classical resources for rare-event sampling. For a fixed stochastic process, the first is the classical-to-quantum ratio of required memory. We show for two example processes that there exists an infinite number of rare-event classes for which the memory ratio for sampling is larger than r , for any large real number r . Then, for a sequence of processes each labeled by an integer size N , we compare how the classical and quantum required memories scale with N . In this setting, since both memories can diverge as N →∞ , the efficiency metric tracks how fast they diverge. An extreme quantum memory advantage exists when the classical memory diverges in the limit N →∞ , but the quantum memory has a finite bound. We then show that finite-state Markov processes and spin chains exhibit memory advantage for sampling of almost all of their rare-event classes.
Extreme Quantum Memory Advantage for Rare-Event Sampling

Directory of Open Access Journals (Sweden)

Cina Aghamohammadi

2018-02-01

Full Text Available We introduce a quantum algorithm for memory-efficient biased sampling of rare events generated by classical memoryful stochastic processes. Two efficiency metrics are used to compare quantum and classical resources for rare-event sampling. For a fixed stochastic process, the first is the classical-to-quantum ratio of required memory. We show for two example processes that there exists an infinite number of rare-event classes for which the memory ratio for sampling is larger than r, for any large real number r. Then, for a sequence of processes each labeled by an integer size N, we compare how the classical and quantum required memories scale with N. In this setting, since both memories can diverge as N→∞, the efficiency metric tracks how fast they diverge. An extreme quantum memory advantage exists when the classical memory diverges in the limit N→∞, but the quantum memory has a finite bound. We then show that finite-state Markov processes and spin chains exhibit memory advantage for sampling of almost all of their rare-event classes.
Rare event simulation in finite-infinite dimensional space

International Nuclear Information System (INIS)

Au, Siu-Kui; Patelli, Edoardo

2016-01-01

Modern engineering systems are becoming increasingly complex. Assessing their risk by simulation is intimately related to the efficient generation of rare failure events. Subset Simulation is an advanced Monte Carlo method for risk assessment and it has been applied in different disciplines. Pivotal to its success is the efficient generation of conditional failure samples, which is generally non-trivial. Conventionally an independent-component Markov Chain Monte Carlo (MCMC) algorithm is used, which is applicable to high dimensional problems (i.e., a large number of random variables) without suffering from ‘curse of dimension’. Experience suggests that the algorithm may perform even better for high dimensional problems. Motivated by this, for any given problem we construct an equivalent problem where each random variable is represented by an arbitrary (hence possibly infinite) number of ‘hidden’ variables. We study analytically the limiting behavior of the algorithm as the number of hidden variables increases indefinitely. This leads to a new algorithm that is more generic and offers greater flexibility and control. It coincides with an algorithm recently suggested by independent researchers, where a joint Gaussian distribution is imposed between the current sample and the candidate. The present work provides theoretical reasoning and insights into the algorithm.
Rare events in networks with internal and external noise

Science.gov (United States)

Hindes, J.; Schwartz, I. B.

2017-12-01

We study rare events in networks with both internal and external noise, and develop a general formalism for analyzing rare events that combines pair-quenched techniques and large-deviation theory. The probability distribution, shape, and time scale of rare events are considered in detail for extinction in the Susceptible-Infected-Susceptible model as an illustration. We find that when both types of noise are present, there is a crossover region as the network size is increased, where the probability exponent for large deviations no longer increases linearly with the network size. We demonstrate that the form of the crossover depends on whether the endemic state is localized near the epidemic threshold or not.
Logistic regression applied to natural hazards: rare event logistic regression with replications

OpenAIRE

Guns, M.; Vanacker, Veerle

2012-01-01

Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logisti...
[Acute renal failure: a rare presentation of Addison's disease].

Science.gov (United States)

Salhi, Houda

2016-01-01

Addison's disease is a rare condition. Its onset of symptoms most often is nonspecific contributing to a diagnostic and therapeutic delay. Acute renal failure can be the first manifestation of this disease. We report the case of a patient with Addison's disease who was initially treated for acute renal failure due to multiple myeloma and whose diagnosis was adjusted thereafter. Patient's condition dramatically improved after treatment with intravenous rehydration; injectable hydrocortisone.
Computing return times or return periods with rare event algorithms

Science.gov (United States)

Lestang, Thibault; Ragone, Francesco; Bréhier, Charles-Edouard; Herbert, Corentin; Bouchet, Freddy

2018-04-01

The average time between two occurrences of the same event, referred to as its return time (or return period), is a useful statistical concept for practical applications. For instance insurances or public agencies may be interested by the return time of a 10 m flood of the Seine river in Paris. However, due to their scarcity, reliably estimating return times for rare events is very difficult using either observational data or direct numerical simulations. For rare events, an estimator for return times can be built from the extrema of the observable on trajectory blocks. Here, we show that this estimator can be improved to remain accurate for return times of the order of the block size. More importantly, we show that this approach can be generalised to estimate return times from numerical algorithms specifically designed to sample rare events. So far those algorithms often compute probabilities, rather than return times. The approach we propose provides a computationally extremely efficient way to estimate numerically the return times of rare events for a dynamical system, gaining several orders of magnitude of computational costs. We illustrate the method on two kinds of observables, instantaneous and time-averaged, using two different rare event algorithms, for a simple stochastic process, the Ornstein–Uhlenbeck process. As an example of realistic applications to complex systems, we finally discuss extreme values of the drag on an object in a turbulent flow.
Laws of small numbers extremes and rare events

CERN Document Server

Falk, Michael; Reiss, Rolf-Dieter

2011-01-01

Since the publication of the first edition of this seminar book in 1994, the theory and applications of extremes and rare events have enjoyed an enormous and still increasing interest. The intention of the book is to give a mathematically oriented development of the theory of rare events underlying various applications. This characteristic of the book was strengthened in the second edition by incorporating various new results. In this third edition, the dramatic change of focus of extreme value theory has been taken into account: from concentrating on maxima of observations it has shifted to l
Trend analysis of cables failure events at nuclear power plants

International Nuclear Information System (INIS)

Fushimi, Yasuyuki

2007-01-01

In this study, 152 failure events related with cables at overseas nuclear power plants are selected from Nuclear Information Database, which is owned by The Institute of Nuclear Safety System, and these events are analyzed in view of occurrence, causal factor, and so on. And 15 failure events related with cables at domestic nuclear power plants are selected from Nuclear Information Archives, which is owned by JANTI, and these events are analyzed by the same manner. As a result of comparing both trends, it is revealed following; 1) A cable insulator failure rate is lower at domestic nuclear power plants than at foreign ones. It is thought that a deterioration diagnosis is performed broadly in Japan. 2) Many buried cables failure events have been occupied a significant portion of cables failure events during work activity at overseas plants, however none has been occurred at domestic plants. It is thought that sufficient survey is conducted before excavating activity in Japan. 3) A domestic age related cables failure rate in service is lower than the overseas one and domestic improper maintenance rate is higher than the overseas one. Maintenance worker' a skill improvement is expected in order to reduce improper maintenance. (author)

Common-Cause Failure Analysis in Event Assessment

International Nuclear Information System (INIS)

Rasmuson, D.M.; Kelly, D.L.

2008-01-01

This paper reviews the basic concepts of modeling common-cause failures (CCFs) in reliability and risk studies and then applies these concepts to the treatment of CCF in event assessment. The cases of a failed component (with and without shared CCF potential) and a component being unavailable due to preventive maintenance or testing are addressed. The treatment of two related failure modes (e.g. failure to start and failure to run) is a new feature of this paper, as is the treatment of asymmetry within a common-cause component group
Logistic regression applied to natural hazards: rare event logistic regression with replications

Science.gov (United States)

Guns, M.; Vanacker, V.

2012-06-01

Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logistic regression with replications, combines the strength of probabilistic and statistical methods, and allows overcoming some of the limitations of previous developments through robust variable selection. This technique was here developed for the analyses of landslide controlling factors, but the concept is widely applicable for statistical analyses of natural hazards.
Logistic regression applied to natural hazards: rare event logistic regression with replications

Directory of Open Access Journals (Sweden)

M. Guns

2012-06-01

Full Text Available Statistical analysis of natural hazards needs particular attention, as most of these phenomena are rare events. This study shows that the ordinary rare event logistic regression, as it is now commonly used in geomorphologic studies, does not always lead to a robust detection of controlling factors, as the results can be strongly sample-dependent. In this paper, we introduce some concepts of Monte Carlo simulations in rare event logistic regression. This technique, so-called rare event logistic regression with replications, combines the strength of probabilistic and statistical methods, and allows overcoming some of the limitations of previous developments through robust variable selection. This technique was here developed for the analyses of landslide controlling factors, but the concept is widely applicable for statistical analyses of natural hazards.
History, rare, and multiple events of mechanical unfolding of repeat proteins

Science.gov (United States)

Sumbul, Fidan; Marchesi, Arin; Rico, Felix

2018-03-01

Mechanical unfolding of proteins consisting of repeat domains is an excellent tool to obtain large statistics. Force spectroscopy experiments using atomic force microscopy on proteins presenting multiple domains have revealed that unfolding forces depend on the number of folded domains (history) and have reported intermediate states and rare events. However, the common use of unspecific attachment approaches to pull the protein of interest holds important limitations to study unfolding history and may lead to discarding rare and multiple probing events due to the presence of unspecific adhesion and uncertainty on the pulling site. Site-specific methods that have recently emerged minimize this uncertainty and would be excellent tools to probe unfolding history and rare events. However, detailed characterization of these approaches is required to identify their advantages and limitations. Here, we characterize a site-specific binding approach based on the ultrastable complex dockerin/cohesin III revealing its advantages and limitations to assess the unfolding history and to investigate rare and multiple events during the unfolding of repeated domains. We show that this approach is more robust, reproducible, and provides larger statistics than conventional unspecific methods. We show that the method is optimal to reveal the history of unfolding from the very first domain and to detect rare events, while being more limited to assess intermediate states. Finally, we quantify the forces required to unfold two molecules pulled in parallel, difficult when using unspecific approaches. The proposed method represents a step forward toward more reproducible measurements to probe protein unfolding history and opens the door to systematic probing of rare and multiple molecule unfolding mechanisms.
A new method for explicit modelling of single failure event within different common cause failure groups

International Nuclear Information System (INIS)

Kančev, Duško; Čepin, Marko

2012-01-01

Redundancy and diversity are the main principles of the safety systems in the nuclear industry. Implementation of safety components redundancy has been acknowledged as an effective approach for assuring high levels of system reliability. The existence of redundant components, identical in most of the cases, implicates a probability of their simultaneous failure due to a shared cause—a common cause failure. This paper presents a new method for explicit modelling of single component failure event within multiple common cause failure groups simultaneously. The method is based on a modification of the frequently utilised Beta Factor parametric model. The motivation for development of this method lays in the fact that one of the most widespread softwares for fault tree and event tree modelling as part of the probabilistic safety assessment does not comprise the option for simultaneous assignment of single failure event to multiple common cause failure groups. In that sense, the proposed method can be seen as an advantage of the explicit modelling of common cause failures. A standard standby safety system is selected as a case study for application and study of the proposed methodology. The results and insights implicate improved, more transparent and more comprehensive models within probabilistic safety assessment.
Anti-glomerular basement membrane: A rare cause of renal failure in children

Directory of Open Access Journals (Sweden)

Indira Agarwal

2017-01-01

Full Text Available Anti-glomerular basement membrane (GBM disease is a rare cause of acute renal failure and known to have bad prognosis regarding renal functions recovery and patient survival specially when diagnosed late and presents with severe renal failure that requires dialysis. We report a case of 11-year-old child with acute renal failure secondary to anti-GBM disease and associated with antineutrophil cytoplasmic antibody-positive vasculitis. He was treated with plasmapheresis, steroids, and cyclophosphamide with recovery of his kidney functions.
Sampling rare events in nonequilibrium and nonstationary systems.

Science.gov (United States)

Berryman, Joshua T; Schilling, Tanja

2010-12-28

Although many computational methods for rare event sampling exist, this type of calculation is not usually practical for general nonequilibrium conditions, with macroscopically irreversible dynamics and away from both stationary and metastable states. A novel method for calculating the time-series of the probability of a rare event is presented which is designed for these conditions. The method is validated for the cases of the Glauber-Ising model under time-varying shear flow, the Kawasaki-Ising model after a quench into the region between nucleation dominated and spinodal decomposition dominated phase change dynamics, and the parallel open asymmetric exclusion process. The method requires a subdivision of the phase space of the system: it is benchmarked and found to scale well for increasingly fine subdivisions, meaning that it can be applied without detailed foreknowledge of the physically important reaction pathways.
Estimating the Probability of a Rare Event Over a Finite Time Horizon

NARCIS (Netherlands)

de Boer, Pieter-Tjerk; L'Ecuyer, Pierre; Rubino, Gerardo; Tuffin, Bruno

2007-01-01

We study an approximation for the zero-variance change of measure to estimate the probability of a rare event in a continuous-time Markov chain. The rare event occurs when the chain reaches a given set of states before some fixed time limit. The jump rates of the chain are expressed as functions of
Analysis of failure events for expansion joints in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Sato, Masahiro [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

Although a large number of expansion joints are used in nuclear power plants with light water reactors, their failure events have not been paid as much attention as those of vessels and pipes. However, as the operation period of nuclear power plants becomes longer, it is necessary to pay attention to their failure events as well as those of vessels and pipes, because aging problems and latent troubles originated in design or fabrication of expansion joints may appear during their long period operation. In this work, we investigated failure event reports of expansion joints in nuclear power plants both in Japan and in U.S.A. and analyzed (1) the influence to output power level, (2) the position and (3) the cause of each failure. It is revealed that the failure events of expansion joints have continuously occurred, some of which have exerted influence upon power level and have caused fatal or injury accidents of personnel, and hence the importance of corrective actions to prevent the recurrence of such events is pointed out. The importance of countermeasures to the following individual events is also pointed out: (1) corrosion of expansion joints in service water systems, (2) degradation of rubber expansion joints in main condensers, (3) vibration and fatigue of expansion joints in extraction steam lines and (4) transgranular stress corrosion cracking of penetration bellows of containments. (author)
Failure diagnosis using discrete event models

International Nuclear Information System (INIS)

Sampath, M.; Sengupta, R.; Lafortune, S.; Teneketzis, D.; Sinnamohideen, K.

1994-01-01

We propose a Discrete Event Systems (DES) approach to the failure diagnosis problem. We present a methodology for modeling physical systems in a DES framework. We discuss the notion of diagnosability and present the construction procedure of the diagnoser. Finally, we illustrate our approach using a Heating, Ventilation and Air Conditioning (HVAC) system
Software failure events derivation and analysis by frame-based technique

International Nuclear Information System (INIS)

Huang, H.-W.; Shih, C.; Yih, Swu; Chen, M.-H.

2007-01-01

A frame-based technique, including physical frame, logical frame, and cognitive frame, was adopted to perform digital I and C failure events derivation and analysis for generic ABWR. The physical frame was structured with a modified PCTran-ABWR plant simulation code, which was extended and enhanced on the feedwater system, recirculation system, and steam line system. The logical model is structured with MATLAB, which was incorporated into PCTran-ABWR to improve the pressure control system, feedwater control system, recirculation control system, and automated power regulation control system. As a result, the software failure of these digital control systems can be properly simulated and analyzed. The cognitive frame was simulated by the operator awareness status in the scenarios. Moreover, via an internal characteristics tuning technique, the modified PCTran-ABWR can precisely reflect the characteristics of the power-core flow. Hence, in addition to the transient plots, the analysis results can then be demonstrated on the power-core flow map. A number of postulated I and C system software failure events were derived to achieve the dynamic analyses. The basis for event derivation includes the published classification for software anomalies, the digital I and C design data for ABWR, chapter 15 accident analysis of generic SAR, and the reported NPP I and C software failure events. The case study of this research includes: (1) the software CMF analysis for the major digital control systems; and (2) postulated ABWR digital I and C software failure events derivation from the actual happening of non-ABWR digital I and C software failure events, which were reported to LER of USNRC or IRS of IAEA. These events were analyzed by PCTran-ABWR. Conflicts among plant status, computer status, and human cognitive status are successfully identified. The operator might not easily recognize the abnormal condition, because the computer status seems to progress normally. However, a well
Laws of small numbers extremes and rare events

CERN Document Server

Falk, Michael; Hüsler, Jürg

2004-01-01

Since the publication of the first edition of this seminar book in 1994, the theory and applications of extremes and rare events have enjoyed an enormous and still increasing interest. The intention of the book is to give a mathematically oriented development of the theory of rare events underlying various applications. This characteristic of the book was strengthened in the second edition by incorporating various new results on about 130 additional pages. Part II, which has been added in the second edition, discusses recent developments in multivariate extreme value theory. Particularly notable is a new spectral decomposition of multivariate distributions in univariate ones which makes multivariate questions more accessible in theory and practice. One of the most innovative and fruitful topics during the last decades was the introduction of generalized Pareto distributions in the univariate extreme value theory. Such a statistical modelling of extremes is now systematically developed in the multivariate fram...
PyRETIS: A well-done, medium-sized python library for rare events.

Science.gov (United States)

Lervik, Anders; Riccardi, Enrico; van Erp, Titus S

2017-10-30

Transition path sampling techniques are becoming common approaches in the study of rare events at the molecular scale. More efficient methods, such as transition interface sampling (TIS) and replica exchange transition interface sampling (RETIS), allow the investigation of rare events, for example, chemical reactions and structural/morphological transitions, in a reasonable computational time. Here, we present PyRETIS, a Python library for performing TIS and RETIS simulations. PyRETIS directs molecular dynamics (MD) simulations in order to sample rare events with unbiased dynamics. PyRETIS is designed to be easily interfaced with any molecular simulation package and in the present release, it has been interfaced with GROMACS and CP2K, for classical and ab initio MD simulations, respectively. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Development of IPRO-ZONE to Determine Component Failure Modes Affected by a Fire Event

International Nuclear Information System (INIS)

Kang, Dae Il; Han, Sang Hoon

2010-01-01

A Fire PSA requires a PSA analyst to select internal initiating events and to determine component failure modes for fire occurrence event of each fire compartment. The component failure modes caused by a fire depend on the several factors. These factors are whether components and their relating equipment and cables are located at fire initiation and propagation compartments or not, fire effects on control and power cables for components and their relating equipment, designed failure modes of component, success criteria in a PSA model, etc. Up to the present, a PSA analyst has been manually determining component failure modes based on criteria mentioned above. This task is one of the difficult works required for fire PSA expertise. In addition, since it requires much information, a fire PSA analyst may have difficulty in maintaining consistency for determining the component failure modes and documentation for them. After determining the component failure modes, internal PSA basic events corresponding to the component failure modes are selected and fire events are modeled for the selected basic events if required. KAERI has been developing the IPRO-ZONE (interface program for constructing zone effect table) to determine component failure modes affected by a fire, to select the internal PSA basic events, and to generate fire events to be modeled. In this paper, we introduce the overview of the IPRO-ZONE and approaches for determining component failure modes implemented in the IPRO-ZONE
Rare Events and Conditional Events on Random Strings

Directory of Open Access Journals (Sweden)

Mireille Régnier

2004-12-01

Full Text Available Some strings -the texts- are assumed to be randomly generated, according to a probability model that is either a Bernoulli model or a Markov model. A rare event is the over or under-representation of a word or a set of words. The aim of this paper is twofold. First, a single word is given. One studies the tail distribution of the number of its occurrences. Sharp large deviation estimates are derived. Second, one assumes that a given word is overrepresented. The distribution of a second word is studied; formulae for the expectation and the variance are derived. In both cases, the formulae are accurate and actually computable. These results have applications in computational biology, where a genome is viewed as a text.
Estimating rare events in biochemical systems using conditional sampling

Science.gov (United States)

Sundar, V. S.

2017-01-01

The paper focuses on development of variance reduction strategies to estimate rare events in biochemical systems. Obtaining this probability using brute force Monte Carlo simulations in conjunction with the stochastic simulation algorithm (Gillespie's method) is computationally prohibitive. To circumvent this, important sampling tools such as the weighted stochastic simulation algorithm and the doubly weighted stochastic simulation algorithm have been proposed. However, these strategies require an additional step of determining the important region to sample from, which is not straightforward for most of the problems. In this paper, we apply the subset simulation method, developed as a variance reduction tool in the context of structural engineering, to the problem of rare event estimation in biochemical systems. The main idea is that the rare event probability is expressed as a product of more frequent conditional probabilities. These conditional probabilities are estimated with high accuracy using Monte Carlo simulations, specifically the Markov chain Monte Carlo method with the modified Metropolis-Hastings algorithm. Generating sample realizations of the state vector using the stochastic simulation algorithm is viewed as mapping the discrete-state continuous-time random process to the standard normal random variable vector. This viewpoint opens up the possibility of applying more sophisticated and efficient sampling schemes developed elsewhere to problems in stochastic chemical kinetics. The results obtained using the subset simulation method are compared with existing variance reduction strategies for a few benchmark problems, and a satisfactory improvement in computational time is demonstrated.
Recommendations for the tuning of rare event probability estimators

International Nuclear Information System (INIS)

Balesdent, Mathieu; Morio, Jérôme; Marzat, Julien

2015-01-01

Being able to accurately estimate rare event probabilities is a challenging issue in order to improve the reliability of complex systems. Several powerful methods such as importance sampling, importance splitting or extreme value theory have been proposed in order to reduce the computational cost and to improve the accuracy of extreme probability estimation. However, the performance of these methods is highly correlated with the choice of tuning parameters, which are very difficult to determine. In order to highlight recommended tunings for such methods, an empirical campaign of automatic tuning on a set of representative test cases is conducted for splitting methods. It allows to provide a reduced set of tuning parameters that may lead to the reliable estimation of rare event probability for various problems. The relevance of the obtained result is assessed on a series of real-world aerospace problems
Calcification of the heart: A rare manifestation of chronic renal failure

International Nuclear Information System (INIS)

Moraes, C.R. de

1986-01-01

A case is presented in which chronic renal failure led to intense visceral calcification, mainly to the lungs and heart. The discovery of cardiac calcifications on plain chest radiographs is exceedingly rare in renal patients. Puncate calcific deposits with an almost homogeneous distribution throughout the cardiac muscle were the main feature of this case. (orig.)
Development of Time Projection Chambers with Micromegas for Rare Event Searches

CERN Document Server

Tomas, Alfredo; Villar, J A

The Rare Event Searches is a heterogeneous field from the point of view of their physical motivations: double betha neutrinoless decay experiments, direct detection of WIMPs as well as axions and other WISPs (candidates for the DM, but also motivated by other questions from Particle Physics). The field is rather defined by the requirements of these experiments, essentially a very sensitive detector with low background which is usually operated in underground laboratories. The availability of a rich description of the event registered by the detector is a powerful tool for the discrimination of the signal from the background. The topological description of the interaction that can be delivered by a gaseous TPC is a useful source of information about the event. The generic requirements for a gaseous TPC that is intended for rare event searches are very good imaging capabilities, high gain and efficiency, stability and reliability and radio-purity, which could imply working with particular gases, in absence of q...
Exploitation of a component event data bank for common cause failure analysis

International Nuclear Information System (INIS)

Games, A.M.; Amendola, A.; Martin, P.

1985-01-01

Investigations into using the European Reliability Data System Component Event Data Bank for common cause failure analysis have been carried out. Starting from early exercises where data were analyzed without computer aid, different types of linked multiple failures have been identified. A classification system is proposed based on this experience. It defines a multiple failure event space wherein each category defines causal, modal, temporal and structural links between failures. It is shown that a search algorithm which incorporates the specific interrogative procedures of the data bank can be developed in conjunction with this classification system. It is concluded that the classification scheme and the search algorithm are useful organizational tools in the field of common cause failures studies. However, it is also suggested that the use of the term common cause failure should be avoided since it embodies to many different types of linked multiple failures

A method for estimating failure rates for low probability events arising in PSA

International Nuclear Information System (INIS)

Thorne, M.C.; Williams, M.M.R.

1995-01-01

The authors develop a method for predicting failure rates and failure probabilities per event when, over a given test period or number of demands, no failures have occurred. A Bayesian approach is adopted to calculate a posterior probability distribution for the failure rate or failure probability per event subsequent to the test period. This posterior is then used to estimate effective failure rates or probabilities over a subsequent period of time or number of demands. In special circumstances, the authors results reduce to the well-known rules of thumb, viz: 1/N and 1/T, where N is the number of demands during the test period for no failures and T is the test period for no failures. However, the authors are able to give strict conditions on the validity of these rules of thumb and to improve on them when necessary
Acute Kidney Injury and Risk of Heart Failure and Atherosclerotic Events.

Science.gov (United States)

Go, Alan S; Hsu, Chi-Yuan; Yang, Jingrong; Tan, Thida C; Zheng, Sijie; Ordonez, Juan D; Liu, Kathleen D

2018-05-17

AKI in the hospital is common and is associated with excess mortality. We examined whether AKI is also independently associated with a higher risk of different cardiovascular events in the first year after discharge. We conducted a retrospective analysis of a cohort between 2006 and 2013 with follow-up through 2014, within Kaiser Permanente Northern California. We identified all adults admitted to 21 hospitals who had one or more in-hospital serum creatinine test result and survived to discharge. Occurrence of AKI was on the basis of Kidney Disease: Improving Global Outcomes diagnostic criteria. Potential confounders were identified from comprehensive inpatient and outpatient, laboratory, and pharmacy electronic medical records. During the 365 days after discharge, we ascertained occurrence of heart failure, acute coronary syndromes, peripheral artery disease, and ischemic stroke events from electronic medical records. Among a matched cohort of 146,941 hospitalized adults, 31,245 experienced AKI. At 365 days postdischarge, AKI was independently associated with higher rates of the composite outcome of hospitalization for heart failure and atherosclerotic events (adjusted hazard ratio [aHR], 1.18; 95% confidence interval [95% CI], 1.13 to 1.25) even after adjustment for demographics, comorbidities, preadmission eGFR and proteinuria, heart failure and sepsis complicating the hospitalization, intensive care unit (ICU) admission, length of stay, and predicted in-hospital mortality. This was driven by an excess risk of subsequent heart failure (aHR, 1.44; 95% CI, 1.33 to 1.56), whereas there was no significant association with follow-up atherosclerotic events (aHR, 1.05; 95% CI, 0.98 to 1.12). AKI is independently associated with a higher risk of cardiovascular events, especially heart failure, after hospital discharge. Copyright © 2018 by the American Society of Nephrology.
GIS-based rare events logistic regression for mineral prospectivity mapping

Science.gov (United States)

Xiong, Yihui; Zuo, Renguang

2018-02-01

Mineralization is a special type of singularity event, and can be considered as a rare event, because within a specific study area the number of prospective locations (1s) are considerably fewer than the number of non-prospective locations (0s). In this study, GIS-based rare events logistic regression (RELR) was used to map the mineral prospectivity in the southwestern Fujian Province, China. An odds ratio was used to measure the relative importance of the evidence variables with respect to mineralization. The results suggest that formations, granites, and skarn alterations, followed by faults and aeromagnetic anomaly are the most important indicators for the formation of Fe-related mineralization in the study area. The prediction rate and the area under the curve (AUC) values show that areas with higher probability have a strong spatial relationship with the known mineral deposits. Comparing the results with original logistic regression (OLR) demonstrates that the GIS-based RELR performs better than OLR. The prospectivity map obtained in this study benefits the search for skarn Fe-related mineralization in the study area.
The FLARES project: An innovative detector technology for rare events searches

Energy Technology Data Exchange (ETDEWEB)

Capelli, S., E-mail: capelli@mib.infn.it [Dipatimento di Fisica, Università di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); INFN Sezione di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); Baldazzi, G. [Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); INFN Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); Beretta, M. [Dipatimento di Fisica, Università di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); INFN Sezione di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); Bonvicini, V. [Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Roberto Cozzi 55, 20126 Milano (Italy); Campana, R. [Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); INFN Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); Evangelista, Y. [INAF - IAPS, Via del Fosso del Cavaliere 100, I-00133, Roma (Italy); INFN Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma (Italy); Fasoli, M. [INFN Sezione di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Roberto Cozzi 55, 20126 Milano (Italy); Feroci, M. [INAF - IAPS, Via del Fosso del Cavaliere 100, I-00133, Roma (Italy); INFN Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, I-00133 Roma (Italy); Fuschino, F. [INFN Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna (Italy); Gironi, L. [Dipatimento di Fisica, Università di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); INFN Sezione di Milano Bicocca, piazza della Scienza 3, 20126 Milano (Italy); and others

2017-02-11

FLARES is an innovative project in the field of rare events searches, such as the search for the neutrinoless double beta decay. It aims at demonstrating the high potential of a technique that combines ultra-pure scintillating crystals with arrays of high performance silicon drift detectors, operated at about 120 K, to reach a 1% level energy resolution. The proposed technique will combine in a single device all the demanding features needed by an ideal experiment looking for rare events. The performance of a first production of matrices of silicon drift detectors as well as first measurements of the low temperature light yield of a selection of high purity scintillating crystals will be presented and discussed.
Classic Bartter syndrome: a rare cause of failure to thrive in a child.

Science.gov (United States)

Vieira, Helena; Mendes, Leonor; Mendes, Patricia; da Silva, José Esteves

2012-06-28

Bartter syndrome is a group of rare autosomal-recessive disorders caused by a defect in distal tubule transport of sodium and chloride. Blood gases and plasma electrolytes raise suspicion of this diagnosis and the definitive diagnosis is made by genetic study. Early treatment improves prognosis. The authors present the case of an 11-month-old child with early failure to thrive and severe regurgitation. Blood gases revealed hypochloraemic metabolic alkalosis, hyponatraemia and hypokalaemia. Blood pressure was normal and polyuria was documented. She began therapy with potassium chloride supplementation and indomethacin. There was clinical improvement and plasma potassium and bicarbonate normalised. The molecular study confirmed it was the classic form of Bartter syndrome. Despite being rare in clinical practice, which may lead to unnecessary medical investigation and diagnosis delay, in a child with failure to thrive, hypochloraemic metabolic alkalosis and hypokalaemia, this diagnosis must be considered.
Acute Renal Failure due to Non-Traumatic Rhabdomyolysis

Directory of Open Access Journals (Sweden)

Nagehan Aslan

2016-04-01

Full Text Available Rhabdomyolysis is a musculoskeletal clinical and biochemical syndrome which is seen associated with traumatic and non-traumatic causes and is known as muscular dystrophy. Rhabdomyolysis which develops following crush-type trauma (Crush syndrome is rarely seen but is a well-known clinical event in the etiology of acute renal failure. Non-traumatic rhabdomyolysis is rare. The case is here presented of a patient who was diagnosed with rhabdomyolysis on presentation with acute renal failure and to whom repeated dialysis was applied.
Preliminary Analysis of the Common Cause Failure Events for Domestic Nuclear Power Plants

International Nuclear Information System (INIS)

Kang, Daeil; Han, Sanghoon

2007-01-01

It is known that the common cause failure (CCF) events have a great effect on the safety and probabilistic safety assessment (PSA) results of nuclear power plants (NPPs). However, the domestic studies have been mainly focused on the analysis method and modeling of CCF events. Thus, the analysis of the CCF events for domestic NPPs were performed to establish a domestic database for the CCF events and to deliver them to the operation office of the international common cause failure data exchange (ICDE) project. This paper presents the analysis results of the CCF events for domestic nuclear power plants
Analysis of arrhythmic events is useful to detect lead failure earlier in patients followed by remote monitoring.

Science.gov (United States)

Nishii, Nobuhiro; Miyoshi, Akihito; Kubo, Motoki; Miyamoto, Masakazu; Morimoto, Yoshimasa; Kawada, Satoshi; Nakagawa, Koji; Watanabe, Atsuyuki; Nakamura, Kazufumi; Morita, Hiroshi; Ito, Hiroshi

2018-03-01

Remote monitoring (RM) has been advocated as the new standard of care for patients with cardiovascular implantable electronic devices (CIEDs). RM has allowed the early detection of adverse clinical events, such as arrhythmia, lead failure, and battery depletion. However, lead failure was often identified only by arrhythmic events, but not impedance abnormalities. To compare the usefulness of arrhythmic events with conventional impedance abnormalities for identifying lead failure in CIED patients followed by RM. CIED patients in 12 hospitals have been followed by the RM center in Okayama University Hospital. All transmitted data have been analyzed and summarized. From April 2009 to March 2016, 1,873 patients have been followed by the RM center. During the mean follow-up period of 775 days, 42 lead failure events (atrial lead 22, right ventricular pacemaker lead 5, implantable cardioverter defibrillator [ICD] lead 15) were detected. The proportion of lead failures detected only by arrhythmic events, which were not detected by conventional impedance abnormalities, was significantly higher than that detected by impedance abnormalities (arrhythmic event 76.2%, 95% CI: 60.5-87.9%; impedance abnormalities 23.8%, 95% CI: 12.1-39.5%). Twenty-seven events (64.7%) were detected without any alert. Of 15 patients with ICD lead failure, none has experienced inappropriate therapy. RM can detect lead failure earlier, before clinical adverse events. However, CIEDs often diagnose lead failure as just arrhythmic events without any warning. Thus, to detect lead failure earlier, careful human analysis of arrhythmic events is useful. © 2017 Wiley Periodicals, Inc.
Rare event simulation in radiation transport

International Nuclear Information System (INIS)

Kollman, C.

1993-10-01

This dissertation studies methods for estimating extremely small probabilities by Monte Carlo simulation. Problems in radiation transport typically involve estimating very rare events or the expected value of a random variable which is with overwhelming probability equal to zero. These problems often have high dimensional state spaces and irregular geometries so that analytic solutions are not possible. Monte Carlo simulation must be used to estimate the radiation dosage being transported to a particular location. If the area is well shielded the probability of any one particular particle getting through is very small. Because of the large number of particles involved, even a tiny fraction penetrating the shield may represent an unacceptable level of radiation. It therefore becomes critical to be able to accurately estimate this extremely small probability. Importance sampling is a well known technique for improving the efficiency of rare event calculations. Here, a new set of probabilities is used in the simulation runs. The results are multiple by the likelihood ratio between the true and simulated probabilities so as to keep the estimator unbiased. The variance of the resulting estimator is very sensitive to which new set of transition probabilities are chosen. It is shown that a zero variance estimator does exist, but that its computation requires exact knowledge of the solution. A simple random walk with an associated killing model for the scatter of neutrons is introduced. Large deviation results for optimal importance sampling in random walks are extended to the case where killing is present. An adaptive ''learning'' algorithm for implementing importance sampling is given for more general Markov chain models of neutron scatter. For finite state spaces this algorithm is shown to give with probability one, a sequence of estimates converging exponentially fast to the true solution
Lost in a random forest: Using Big Data to study rare events

Directory of Open Access Journals (Sweden)

Christopher A Bail

2015-12-01

Full Text Available Sudden, broad-scale shifts in public opinion about social problems are relatively rare. Until recently, social scientists were forced to conduct post-hoc case studies of such unusual events that ignore the broader universe of possible shifts in public opinion that do not materialize. The vast amount of data that has recently become available via social media sites such as Facebook and Twitter—as well as the mass-digitization of qualitative archives provide an unprecedented opportunity for scholars to avoid such selection on the dependent variable. Yet the sheer scale of these new data creates a new set of methodological challenges. Conventional linear models, for example, minimize the influence of rare events as “outliers”—especially within analyses of large samples. While more advanced regression models exist to analyze outliers, they suffer from an even more daunting challenge: equifinality, or the likelihood that rare events may occur via different causal pathways. I discuss a variety of possible solutions to these problems—including recent advances in fuzzy set theory and machine learning—but ultimately advocate an ecumenical approach that combines multiple techniques in iterative fashion.
Towards a whole-network risk assessment for railway bridge failures caused by scour during flood events

Directory of Open Access Journals (Sweden)

Lamb Rob

2016-01-01

Full Text Available Localised erosion (scour during flood flow conditions can lead to costly damage or catastrophic failure of bridges, and in some cases loss of life or significant disruption to transport networks. Here, we take a broad scale view to assess risk associated with bridge scour during flood events over an entire infrastructure network, illustrating the analysis with data from the British railways. There have been 54 recorded events since 1846 in which scour led to the failure of railway bridges in Britain. These events tended to occur during periods of extremely high river flow, although there is uncertainty about the precise conditions under which failures occur, which motivates a probabilistic analysis of the failure events. We show how data from the historical bridge failures, combined with hydrological analysis, have been used to construct fragility curves that quantify the conditional probability of bridge failure as a function of river flow, accompanied by estimates of the associated uncertainty. The new fragility analysis is tested using flood events simulated from a national, spatial joint probability model for extremes in river flows. The combined models appear robust in comparison with historical observations of the expected number of bridge failures in a flood event, and provide an empirical basis for further broad-scale network risk analysis.
Inferring phylogenetic trees from the knowledge of rare evolutionary events.

Science.gov (United States)

Hellmuth, Marc; Hernandez-Rosales, Maribel; Long, Yangjing; Stadler, Peter F

2018-06-01

Rare events have played an increasing role in molecular phylogenetics as potentially homoplasy-poor characters. In this contribution we analyze the phylogenetic information content from a combinatorial point of view by considering the binary relation on the set of taxa defined by the existence of a single event separating two taxa. We show that the graph-representation of this relation must be a tree. Moreover, we characterize completely the relationship between the tree of such relations and the underlying phylogenetic tree. With directed operations such as tandem-duplication-random-loss events in mind we demonstrate how non-symmetric information constrains the position of the root in the partially reconstructed phylogeny.
Tentorial and dural calcification with tertiary hyperparathyroidism: a rare entity in chronic renal failure

International Nuclear Information System (INIS)

Dorenbeck, U.; Bretschneider, T.; Feuerbach, S.; Leingaertner, T.; Kraemer, B.K.

2002-01-01

A case of rare calcification of the tentorium cerebelli, the thoracal dura mater of the spine, and the sclera in an adult male patient with tertiary hyperparathyroidism is presented. The often reported feature in the skull is that of a combination of osteopenia and osteosclerosis giving a granular bone texture. Extensive dura calcification with this condition has very rarely been reported. It is the aim of this paper to document the latter in a patient with chronic renal failure and tertiary hyperparathyroidism. (orig.)
Coexistence of chronic renal failure, hashimoto thyroiditis and idiopathic hypoparathyroidism: a rare case report.

Science.gov (United States)

Yildiz, Saliha; Soyoral, Yasemin; Demirkiran, Davut; Ozturk, Mustafa

2014-04-01

Hypoparathyroidism is an uncommon disease and its coexistence with chronic renal failure is quite rare. Hypocalcemia and hyperphosphatemia are seen in both diseases. Diagnosis of hypoparathyroidism may be overlooked when parathormone response is not evaluated in patients with chronic renal failure. A 19-year-old female patient who had been receiving hemodialysis for 3 years because of chronic renal failure was diagnosed as idiopathic hypoparathyroidism and hashimoto thyroiditis. When her medical records on the first admission and medical history were evaluated, hypoparathyroidism and hashimoto thyroiditis were seen to be present also when she was started hemodialysis. Idiopathic hypoparathyroidism should be suspected in case as absence of parathormone response to hypocalcemia in patients with chronic renal failure. It should be taken into consideration that hashimoto thyroiditis may accompany and required analysis should be done.
Statistical analysis of events related to emergency diesel generators failures in the nuclear industry

Energy Technology Data Exchange (ETDEWEB)

Kančev, Duško, E-mail: dusko.kancev@ec.europa.eu [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Duchac, Alexander; Zerger, Benoit [European Commission, DG-JRC, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Maqua, Michael [Gesellschaft für Anlagen-und-Reaktorsicherheit (GRS) mbH, Schwetnergasse 1, 50667 Köln (Germany); Wattrelos, Didier [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), BP 17 - 92262 Fontenay-aux-Roses Cedex (France)

2014-07-01

Highlights: • Analysis of operating experience related to emergency diesel generators events at NPPs. • Four abundant operating experience databases screened. • Delineating important insights and conclusions based on the operating experience. - Abstract: This paper is aimed at studying the operating experience related to emergency diesel generators (EDGs) events at nuclear power plants collected from the past 20 years. Events related to EDGs failures and/or unavailability as well as all the supporting equipment are in the focus of the analysis. The selected operating experience was analyzed in detail in order to identify the type of failures, attributes that contributed to the failure, failure modes potential or real, discuss risk relevance, summarize important lessons learned, and provide recommendations. The study in this particular paper is tightly related to the performing of statistical analysis of the operating experience. For the purpose of this study EDG failure is defined as EDG failure to function on demand (i.e. fail to start, fail to run) or during testing, or an unavailability of an EDG, except of unavailability due to regular maintenance. The Gesellschaft für Anlagen und Reaktorsicherheit mbH (GRS) and Institut de Radioprotection et de Sûreté Nucléaire (IRSN) databases as well as the operating experience contained in the IAEA/NEA International Reporting System for Operating Experience and the U.S. Licensee Event Reports were screened. The screening methodology applied for each of the four different databases is presented. Further on, analysis aimed at delineating the causes, root causes, contributing factors and consequences are performed. A statistical analysis was performed related to the chronology of events, types of failures, the operational circumstances of detection of the failure and the affected components/subsystems. The conclusions and results of the statistical analysis are discussed. The main findings concerning the testing
Statistical analysis of events related to emergency diesel generators failures in the nuclear industry

International Nuclear Information System (INIS)

Kančev, Duško; Duchac, Alexander; Zerger, Benoit; Maqua, Michael; Wattrelos, Didier

2014-01-01

Highlights: • Analysis of operating experience related to emergency diesel generators events at NPPs. • Four abundant operating experience databases screened. • Delineating important insights and conclusions based on the operating experience. - Abstract: This paper is aimed at studying the operating experience related to emergency diesel generators (EDGs) events at nuclear power plants collected from the past 20 years. Events related to EDGs failures and/or unavailability as well as all the supporting equipment are in the focus of the analysis. The selected operating experience was analyzed in detail in order to identify the type of failures, attributes that contributed to the failure, failure modes potential or real, discuss risk relevance, summarize important lessons learned, and provide recommendations. The study in this particular paper is tightly related to the performing of statistical analysis of the operating experience. For the purpose of this study EDG failure is defined as EDG failure to function on demand (i.e. fail to start, fail to run) or during testing, or an unavailability of an EDG, except of unavailability due to regular maintenance. The Gesellschaft für Anlagen und Reaktorsicherheit mbH (GRS) and Institut de Radioprotection et de Sûreté Nucléaire (IRSN) databases as well as the operating experience contained in the IAEA/NEA International Reporting System for Operating Experience and the U.S. Licensee Event Reports were screened. The screening methodology applied for each of the four different databases is presented. Further on, analysis aimed at delineating the causes, root causes, contributing factors and consequences are performed. A statistical analysis was performed related to the chronology of events, types of failures, the operational circumstances of detection of the failure and the affected components/subsystems. The conclusions and results of the statistical analysis are discussed. The main findings concerning the testing
Nail patella syndrome: a rare cause of renal failure in a young adult ...

African Journals Online (AJOL)

Nail Patella Syndrome (NPS) is a rare hereditary disease affecting multiple systems with predominant involvement of Kidney, Bones and Nails and Eyes. We report a case of NPS which presented as renal failure in a 22 year old male. The patient was admitted with decreased urine output and features of fluid overload and ...
An Efficient Simulation Method for Rare Events

KAUST Repository

Rached, Nadhir B.

2015-01-07

Estimating the probability that a sum of random variables (RVs) exceeds a given threshold is a well-known challenging problem. Closed-form expressions for the sum distribution do not generally exist, which has led to an increasing interest in simulation approaches. A crude Monte Carlo (MC) simulation is the standard technique for the estimation of this type of probability. However, this approach is computationally expensive, especially when dealing with rare events. Variance reduction techniques are alternative approaches that can improve the computational efficiency of naive MC simulations. We propose an Importance Sampling (IS) simulation technique based on the well-known hazard rate twisting approach, that presents the advantage of being asymptotically optimal for any arbitrary RVs. The wide scope of applicability of the proposed method is mainly due to our particular way of selecting the twisting parameter. It is worth observing that this interesting feature is rarely satisfied by variance reduction algorithms whose performances were only proven under some restrictive assumptions. It comes along with a good efficiency, illustrated by some selected simulation results comparing the performance of our method with that of an algorithm based on a conditional MC technique.
An Efficient Simulation Method for Rare Events

KAUST Repository

Rached, Nadhir B.; Benkhelifa, Fatma; Kammoun, Abla; Alouini, Mohamed-Slim; Tempone, Raul

2015-01-01

Estimating the probability that a sum of random variables (RVs) exceeds a given threshold is a well-known challenging problem. Closed-form expressions for the sum distribution do not generally exist, which has led to an increasing interest in simulation approaches. A crude Monte Carlo (MC) simulation is the standard technique for the estimation of this type of probability. However, this approach is computationally expensive, especially when dealing with rare events. Variance reduction techniques are alternative approaches that can improve the computational efficiency of naive MC simulations. We propose an Importance Sampling (IS) simulation technique based on the well-known hazard rate twisting approach, that presents the advantage of being asymptotically optimal for any arbitrary RVs. The wide scope of applicability of the proposed method is mainly due to our particular way of selecting the twisting parameter. It is worth observing that this interesting feature is rarely satisfied by variance reduction algorithms whose performances were only proven under some restrictive assumptions. It comes along with a good efficiency, illustrated by some selected simulation results comparing the performance of our method with that of an algorithm based on a conditional MC technique.
Rare Events

Science.gov (United States)

2009-10-01

Limited Operational Exercise 1. 1A Limited Operational Exercise is a multiplayer experiment designed to exploit and study information sharing and...1.4 Summary of the Study The “rare event” of interest is an extreme, deliberate act of violence , destruction or socioeconomic disruption, such as an...connection with terrorism inves- tigations. The programs then use some combination of doctrinal revision and rewards to induce the people to abandon violence

Rare events in finite and infinite dimensions

Science.gov (United States)

Reznikoff, Maria G.

Thermal noise introduces stochasticity into deterministic equations and makes possible events which are never seen in the zero temperature setting. The driving force behind the thesis work is a desire to bring analysis and probability to bear on a class of relevant and intriguing physical problems, and in so doing, to allow applications to drive the development of new mathematical theory. The unifying theme is the study of rare events under the influence of small, random perturbations, and the manifold mathematical problems which ensue. In the first part, we apply large deviation theory and prefactor estimates to a coherent rotation micromagnetic model in order to analyze thermally activated magnetic switching. We consider recent physical experiments and the mathematical questions "asked" by them. A stochastic resonance type phenomenon is discovered, leading to the definition of finite temperature astroids. Non-Arrhenius behavior is discussed. The analysis is extended to ramped astroids. In addition, we discover that for low damping and ultrashort pulses, deterministic effects can override thermal effects, in accord with very recent ultrashort pulse experiments. Even more interesting, perhaps, is the study of large deviations in the infinite dimensional context, i.e. in spatially extended systems. Inspired by recent numerical investigations, we study the stochastically perturbed Allen Cahn and Cahn Hilliard equations. For the Allen Cahn equation, we study the action minimization problem (a deterministic variational problem) and prove the action scaling in four parameter regimes, via upper and lower bounds. The sharp interface limit is studied. We formally derive a reduced action functional which lends insight into the connection between action minimization and curvature flow. For the Cahn Hilliard equation, we prove upper and lower bounds for the scaling of the energy barrier in the nucleation and growth regime. Finally, we consider rare events in large or infinite
Efficient rare-event simulation for multiple jump events in regularly varying random walks and compound Poisson processes

NARCIS (Netherlands)

B. Chen (Bohan); J. Blanchet; C.H. Rhee (Chang-Han); A.P. Zwart (Bert)

2017-01-01

textabstractWe propose a class of strongly efficient rare event simulation estimators for random walks and compound Poisson processes with a regularly varying increment/jump-size distribution in a general large deviations regime. Our estimator is based on an importance sampling strategy that hinges
Reliability of piping system components. Volume 4: The pipe failure event database

Energy Technology Data Exchange (ETDEWEB)

Nyman, R; Erixon, S [Swedish Nuclear Power Inspectorate, Stockholm (Sweden); Tomic, B [ENCONET Consulting GmbH, Vienna (Austria); Lydell, B [RSA Technologies, Visat, CA (United States)

1996-07-01

Available public and proprietary databases on piping system failures were searched for relevant information. Using a relational database to identify groupings of piping failure modes and failure mechanisms, together with insights from published PSAs, the project team determined why, how and where piping systems fail. This report represents a compendium of technical issues important to the analysis of pipe failure events, and statistical estimation of failure rates. Inadequacies of traditional PSA methodology are addressed, with directions for PSA methodology enhancements. A `data driven and systems oriented` analysis approach is proposed to enable assignment of unique identities to risk-significant piping system component failure. Sufficient operating experience does exist to generate quality data on piping failures. Passive component failures should be addressed by today`s PSAs to allow for aging analysis and effective, on-line risk management. 42 refs, 25 figs.
Reliability of piping system components. Volume 4: The pipe failure event database

International Nuclear Information System (INIS)

Nyman, R.; Erixon, S.; Tomic, B.; Lydell, B.

1996-07-01

Available public and proprietary databases on piping system failures were searched for relevant information. Using a relational database to identify groupings of piping failure modes and failure mechanisms, together with insights from published PSAs, the project team determined why, how and where piping systems fail. This report represents a compendium of technical issues important to the analysis of pipe failure events, and statistical estimation of failure rates. Inadequacies of traditional PSA methodology are addressed, with directions for PSA methodology enhancements. A 'data driven and systems oriented' analysis approach is proposed to enable assignment of unique identities to risk-significant piping system component failure. Sufficient operating experience does exist to generate quality data on piping failures. Passive component failures should be addressed by today's PSAs to allow for aging analysis and effective, on-line risk management. 42 refs, 25 figs
Rare Event Simulation in Radiation Transport

Science.gov (United States)

Kollman, Craig

This dissertation studies methods for estimating extremely small probabilities by Monte Carlo simulation. Problems in radiation transport typically involve estimating very rare events or the expected value of a random variable which is with overwhelming probability equal to zero. These problems often have high dimensional state spaces and irregular geometries so that analytic solutions are not possible. Monte Carlo simulation must be used to estimate the radiation dosage being transported to a particular location. If the area is well shielded the probability of any one particular particle getting through is very small. Because of the large number of particles involved, even a tiny fraction penetrating the shield may represent an unacceptable level of radiation. It therefore becomes critical to be able to accurately estimate this extremely small probability. Importance sampling is a well known technique for improving the efficiency of rare event calculations. Here, a new set of probabilities is used in the simulation runs. The results are multiplied by the likelihood ratio between the true and simulated probabilities so as to keep our estimator unbiased. The variance of the resulting estimator is very sensitive to which new set of transition probabilities are chosen. It is shown that a zero variance estimator does exist, but that its computation requires exact knowledge of the solution. A simple random walk with an associated killing model for the scatter of neutrons is introduced. Large deviation results for optimal importance sampling in random walks are extended to the case where killing is present. An adaptive "learning" algorithm for implementing importance sampling is given for more general Markov chain models of neutron scatter. For finite state spaces this algorithm is shown to give, with probability one, a sequence of estimates converging exponentially fast to the true solution. In the final chapter, an attempt to generalize this algorithm to a continuous
Detecting failure events in buildings: a numerical and experimental analysis

OpenAIRE

Heckman, V. M.; Kohler, M. D.; Heaton, T. H.

2010-01-01

A numerical method is used to investigate an approach for detecting the brittle fracture of welds associated with beam -column connections in instrumented buildings in real time through the use of time-reversed Green’s functions and wave propagation reciprocity. The approach makes use of a prerecorded catalog of Green’s functions for an instrumented building to detect failure events in the building during a later seismic event by screening continuous data for the presence of wavef...
Study of Rare Events at the Split Field Magnet

CERN Multimedia

2002-01-01

The aim of the experiment is the study of full events associated with special, rare triggers using the almost 4 @p geometry of the improved Split Field Magnet (SFM) detector. Two triggers are used: a) a trigger on an electron produced around 90|0 with a transverse momentum p^t @$>$ 0.5 GeV/c; b) a trigger on very high p^t hadrons (p^t $>$ 5 GeV/c) at @Q @C 45|0, using the SFM chambers to define roads pointing to the interaction region. In the first case, the associated event will be studied to determine the origin of direct electron production in charmed particle production. In the second case, the production of jets or jet-like objects when a high p^t particle is produced in pp collisions will be investigated. To carry out this program, the detection system consists of : \\item a) An improved SFM detector chamber system and layout to detect more of the produced particles and to simplify the pattern recognition problem in multiparticle events. \\item b) An improved program chain for the analysis of SFM events, ...
Bland-White-Garland syndrome - a rare and serious cause of failure to thrive.

Science.gov (United States)

Szmigielska, Agnieszka; Roszkowska-Blaim, Maria; Gołąbek-Dylewska, Małgorzata; Tomik, Agnieszka; Brzewski, Michał; Werner, Bożena

2013-01-01

Male, 0 FINAL DIAGNOSIS: Bland-White-Garland syndrome Symptoms: Cardiomegaly, feeding problems Medication: - Clinical Procedure: Reimplantation of the left coronary artery to the aorta Specialty: Pediatrics and Neonatology. Rare disease. Bland-White-Garland syndrome (BWGS) is a very rare disease characterized by anomalous origin of the left coronary artery from the pulmonary trunk (ALCAPA). WBGS affects 1 in every 300 000 live births. Children typically present with dyspnea, pallor, and failure to thrive. Without surgical repair, most of these children die during the first months of life. This case report describes 3-month-old boy admitted to the hospital because of feeding problems. The boy was born at term, with birth weight 3200 g, and was 10 points in Apgar score. He was breast-fed from birth. From the seventh week of age, his mother observed his increasing difficulties with feeding. Physical examination revealed pale skin, diminished heart sounds, tachycardia, cardiomegaly, and hepatomegaly. Results of urine and blood tests and ultrasonography of the central nervous system and abdomen were normal. The chest radiography showed cardiomegaly and electrocardiogram revealed anterolateral myocardial infarction. On echocardiography, an anomalous left coronary artery arising from the pulmonary artery was found. The life-saving treatment of choice was immediate surgical reimplantation of the left coronary artery to the aorta. Children with congenital heart disease are often prone to malnutrition, but in rare cases failure to thrive and breast-feeding problems can be the first symptoms of life-threatening diseases like myocardial infarction secondary to Bland-White-Garland syndrome (BWGS).
Physics of rare events: insights on Napoleon death

Science.gov (United States)

Fiorini, Ettore

2009-03-01

This unusual report tries to show that the high level of sophistication reached in the instrumentation in experiments on rare events can allow to investigate with unprecedented accuracy problems far from those of fundamental physics, but quite important in other fields of physics. The technique and the know-how on neutron activation developed to reduce the background due to spurious events in the CUORE detector to search for neutrinoless double beta decay has been applied to determine the arsenic contents in the hairs of Napoleon Bonaparte and of historical subjects of his time and to compare it with those of subjects living presently. This contents has been found to be about two orders of magnitude larger than the present ones. The As concentration in the hairs of the Emperor is large, but similar to those of the his contemporaries. In additions a comparison among fraction of one of his hairs allows to exclude a criminal act.
Physics of rare events: insights on Napoleon death

International Nuclear Information System (INIS)

Fiorini, Ettore

2009-01-01

This unusual report tries to show that the high level of sophistication reached in the instrumentation in experiments on rare events can allow to investigate with unprecedented accuracy problems far from those of fundamental physics, but quite important in other fields of physics. The technique and the know-how on neutron activation developed to reduce the background due to spurious events in the CUORE detector to search for neutrinoless double beta decay has been applied to determine the arsenic contents in the hairs of Napoleon Bonaparte and of historical subjects of his time and to compare it with those of subjects living presently. This contents has been found to be about two orders of magnitude larger than the present ones. The As concentration in the hairs of the Emperor is large, but similar to those of the his contemporaries. In additions a comparison among fraction of one of his hairs allows to exclude a criminal act.
Classic Bartter syndrome: a rare cause of failure to thrive in a child

OpenAIRE

Vieira, Helena; Mendes, Leonor; Mendes, Patricia; da Silva, José Esteves

2012-01-01

Bartter syndrome is a group of rare autosomal-recessive disorders caused by a defect in distal tubule transport of sodium and chloride. Blood gases and plasma electrolytes raise suspicion of this diagnosis and the definitive diagnosis is made by genetic study. Early treatment improves prognosis. The authors present the case of an 11-month-old child with early failure to thrive and severe regurgitation. Blood gases revealed hypochloraemic metabolic alkalosis, hyponatraemia and hypokalaemia. Bl...
[Rare cause of heart failure in an elderly woman in Djibouti: left ventricular non compaction].

Science.gov (United States)

Massoure, P L; Lamblin, G; Bertani, A; Eve, O; Kaiser, E

2011-10-01

The purpose of this report is to describe the first case of left ventricular non compaction diagnosed in Djibouti. The patient was a 74-year-old Djiboutian woman with symptomatic heart failure. Echocardiography is the key tool for assessment of left ventricular non compaction. This rare cardiomyopathy is probably underdiagnosed in Africa.
Holt-Oram Syndrome in Adult Presenting with Heart Failure: A Rare Presentation

Directory of Open Access Journals (Sweden)

Rupesh Kumar

2014-01-01

Full Text Available Holt-Oram syndrome is a rare inherited disorder involving the hands, arms, and the heart. The defects involve carpal bones of the wrist and the thumb and the associated cardiac anomalies like atrial or ventricular septal defects. Congenital cardiac and upper-limb malformations frequently occur together and are classified as heart-hand syndromes. The most common amongst the heart-hand disorders is the Holt-Oram syndrome, which is characterized by septal defects of the heart and preaxial radial ray abnormalities. Its incidence is one in 100,000 live births. Approximately three out of four patients have some cardiac abnormality with common associations being either an atrial septal defect or ventricular septal defect. Herein, we report a rare sporadic case of Holt-Oram syndrome with atrial septal defect with symptoms of heart failure in a forty-five-year-old lady who underwent emergency cardiac surgery for the symptoms.
Influential factors of red-light running at signalized intersection and prediction using a rare events logistic regression model.

Science.gov (United States)

Ren, Yilong; Wang, Yunpeng; Wu, Xinkai; Yu, Guizhen; Ding, Chuan

2016-10-01

Red light running (RLR) has become a major safety concern at signalized intersection. To prevent RLR related crashes, it is critical to identify the factors that significantly impact the drivers' behaviors of RLR, and to predict potential RLR in real time. In this research, 9-month's RLR events extracted from high-resolution traffic data collected by loop detectors from three signalized intersections were applied to identify the factors that significantly affect RLR behaviors. The data analysis indicated that occupancy time, time gap, used yellow time, time left to yellow start, whether the preceding vehicle runs through the intersection during yellow, and whether there is a vehicle passing through the intersection on the adjacent lane were significantly factors for RLR behaviors. Furthermore, due to the rare events nature of RLR, a modified rare events logistic regression model was developed for RLR prediction. The rare events logistic regression method has been applied in many fields for rare events studies and shows impressive performance, but so far none of previous research has applied this method to study RLR. The results showed that the rare events logistic regression model performed significantly better than the standard logistic regression model. More importantly, the proposed RLR prediction method is purely based on loop detector data collected from a single advance loop detector located 400 feet away from stop-bar. This brings great potential for future field applications of the proposed method since loops have been widely implemented in many intersections and can collect data in real time. This research is expected to contribute to the improvement of intersection safety significantly. Copyright © 2016 Elsevier Ltd. All rights reserved.
Bland-White-Garland syndrome – a rare and serious cause of failure to thrive

Science.gov (United States)

Szmigielska, Agnieszka; Roszkowska-Blaim, Maria; Gołąbek-Dylewska, Małgorzata; Tomik, Agnieszka; Brzewski, Michał; Werner, Bożena

2013-01-01

Patient: Male, 0 Final Diagnosis: Bland-White-Garland syndrome Symptoms: Cardiomegaly, feeding problems Medication: — Clinical Procedure: Reimplantation of the left coronary artery to the aorta Specialty: Pediatrics and Neonatology Objective: Rare disease Background: Bland-White-Garland syndrome (BWGS) is a very rare disease characterized by anomalous origin of the left coronary artery from the pulmonary trunk (ALCAPA). WBGS affects 1 in every 300 000 live births. Children typically present with dyspnea, pallor, and failure to thrive. Without surgical repair, most of these children die during the first months of life. Case Report: This case report describes 3-month-old boy admitted to the hospital because of feeding problems. The boy was born at term, with birth weight 3200 g, and was 10 points in Apgar score. He was breast-fed from birth. From the seventh week of age, his mother observed his increasing difficulties with feeding. Physical examination revealed pale skin, diminished heart sounds, tachycardia, cardiomegaly, and hepatomegaly. Results of urine and blood tests and ultrasonography of the central nervous system and abdomen were normal. The chest radiography showed cardiomegaly and electrocardiogram revealed anterolateral myocardial infarction. On echocardiography, an anomalous left coronary artery arising from the pulmonary artery was found. The life-saving treatment of choice was immediate surgical reimplantation of the left coronary artery to the aorta. Conclusions: Children with congenital heart disease are often prone to malnutrition, but in rare cases failure to thrive and breast-feeding problems can be the first symptoms of life-threatening diseases like myocardial infarction secondary to Bland-White-Garland syndrome (BWGS). PMID:24086793
Action-Derived Molecular Dynamics in the Study of Rare Events

Energy Technology Data Exchange (ETDEWEB)

Passerone, Daniele; Parrinello, Michele

2001-09-03

We present a practical method to generate classical trajectories with fixed initial and final boundary conditions. Our method is based on the minimization of a suitably defined discretized action. The method finds its most natural application in the study of rare events. Its capabilities are illustrated by nontrivial examples. The algorithm lends itself to straightforward parallelization, and when combined with ab initio molecular dynamics it promises to offer a powerful tool for the study of chemical reactions.
Action-Derived Molecular Dynamics in the Study of Rare Events

International Nuclear Information System (INIS)

Passerone, Daniele; Parrinello, Michele

2001-01-01

We present a practical method to generate classical trajectories with fixed initial and final boundary conditions. Our method is based on the minimization of a suitably defined discretized action. The method finds its most natural application in the study of rare events. Its capabilities are illustrated by nontrivial examples. The algorithm lends itself to straightforward parallelization, and when combined with ab initio molecular dynamics it promises to offer a powerful tool for the study of chemical reactions
Correction to: Progressive multifocal leukoencephalopathy in rituximab-treated rheumatic diseases: a rare event.

Science.gov (United States)

Berger, Joseph R; Malik, Vineeta; Lacey, Stuart; Brunetta, Paul; Lehane, Patricia B

2018-04-10

The article "Progressive multifocal leukoencephalopathy in rituximab-treated rheumatic diseases: a rare event," written by Joseph R. Berger, Vineeta Malik, Stuart Lacey, Paul Brunetta, and Patricia B. Lehane 3 , was originally published electronically on the publisher's internet portal (currently SpringerLink).
Baseline Hemodynamics and Response to Contrast Media During Diagnostic Cardiac Catheterization Predict Adverse Events in Heart Failure Patients.

Science.gov (United States)

Denardo, Scott J; Vock, David M; Schmalfuss, Carsten M; Young, Gregory D; Tcheng, James E; O'Connor, Christopher M

2016-07-01

Contrast media administered during cardiac catheterization can affect hemodynamic variables. However, little is documented about the effects of contrast on hemodynamics in heart failure patients or the prognostic value of baseline and changes in hemodynamics for predicting subsequent adverse events. In this prospective study of 150 heart failure patients, we measured hemodynamics at baseline and after administration of iodixanol or iopamidol contrast. One-year Kaplan-Meier estimates of adverse event-free survival (death, heart failure hospitalization, and rehospitalization) were generated, grouping patients by baseline measures of pulmonary capillary wedge pressure (PCWP) and cardiac index (CI), and by changes in those measures after contrast administration. We used Cox proportional hazards modeling to assess sequentially adding baseline PCWP and change in CI to 5 validated risk models (Seattle Heart Failure Score, ESCAPE [Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness], CHARM [Candesartan in Heart Failure: Assessment of Reduction in Mortality and Morbidity], CORONA [Controlled Rosuvastatin Multinational Trial in Heart Failure], and MAGGIC [Meta-Analysis Global Group in Chronic Heart Failure]). Median contrast volume was 109 mL. Both contrast media caused similarly small but statistically significant changes in most hemodynamic variables. There were 39 adverse events (26.0%). Adverse event rates increased using the composite metric of baseline PCWP and change in CI (Pcontrast correlated with the poorest prognosis. Adding both baseline PCWP and change in CI to the 5 risk models universally improved their predictive value (P≤0.02). In heart failure patients, the administration of contrast causes small but significant changes in hemodynamics. Calculating baseline PCWP with change in CI after contrast predicts adverse events and increases the predictive value of existing models. Patients with elevated baseline PCWP and
The neighbourhood method for measuring differences in maternal mortality, infant mortality and other rare demographic events.

Directory of Open Access Journals (Sweden)

Nurul Alam

Full Text Available In the absence of reliable systems for registering rare types of vital events large surveys are required to measure changes in their rates. However some events such as maternal deaths are widely known about in the community. This study examined the utility of asking respondents about events in their neighbourhood as an efficient method for measuring relative rates of rare health events such as maternal and infant deaths. A survey was conducted in the health and demographic surveillance system (HDSS in Matlab, Bangladesh, which includes two areas with different health care regimes. Adult women were asked about any maternal deaths; multiple births; infant deaths, live births and some other events they knew of in a small specified area around their home. Agreement between HDSS records and survey responses was moderate or better (kappa≥0.44 for all the events and greatest for maternal deaths (kappa = 0.77 with 84% being reported. Most events were more likely to be reported if they were recent (p<0.05. Infant mortality rate in one area was 0.56 times that in the other which was well reflected by the ratio of survey results (0.53. Simulations were used to study the ability of the method to detect differences in maternal mortality ratio. These suggested that a sample size around 5000 would give 80% power to detect a 50% decrease from a baseline of 183 which compared well with an estimated sample size around 10 times larger using the direct sisterhood method. The findings suggest that the Neighbourhood Method has potential for monitoring relative differences between areas or changes over time in the rates of rare demographic events, requiring considerably smaller sample sizes than traditional methods. This raises the possibility for interventions to demonstrate real effects on outcomes such as maternal deaths where previously this was only feasible by indirect methods.

The antioxidant acetylcysteine reduces cardiovascular events in patients with end-stage renal failure: a randomized, controlled trial

DEFF Research Database (Denmark)

Tepel, Martin; van der Giet, Markus; Statz, Mario

2003-01-01

Patients with end-stage renal failure have increased oxidative stress and show elevated cardiovascular mortality. Whether increased cardiovascular events can be prevented by the administration of antioxidants is unknown.......Patients with end-stage renal failure have increased oxidative stress and show elevated cardiovascular mortality. Whether increased cardiovascular events can be prevented by the administration of antioxidants is unknown....
Improved methods for dependent failure analysis in PSA

International Nuclear Information System (INIS)

Ballard, G.M.; Games, A.M.

1988-01-01

The basic design principle used in ensuring the safe operation of nuclear power plant is defence in depth. This normally takes the form of redundant equipment and systems which provide protection even if a number of equipment failures occur. Such redundancy is particularly effective in ensuring that multiple, independent equipment failures with the potential for jeopardising reactor safety will be rare events. However the achievement of high reliability has served to highlight the potentially dominant role of multiple, dependent failures of equipment and systems. Analysis of reactor operating experience has shown that dependent failure events are the major contributors to safety system failures and reactor incidents and accidents. In parallel PSA studies have shown that the results of a safety analysis are sensitive to assumptions made about the dependent failure (CCF) probability for safety systems. Thus a Westinghouse Analysis showed that increasing system dependent failure probabilities by a factor of 5 led to a factor 4 increase in core. This paper particularly refers to the engineering concepts underlying dependent failure assessment touching briefly on aspects of data. It is specifically not the intent of our work to develop a new mathematical model of CCF but to aid the use of existing models
How to Cope with the Rare Human Error Events Involved with organizational Factors in Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Kim, Sa Kil; Luo, Meiling; Lee, Yong Hee [Korea Atomic Research Institute, Daejeon (Korea, Republic of)

2014-10-15

The current human error guidelines (e.g. US DOD handbooks, US NRC Guidelines) are representative tools to prevent human errors. These tools, however, have limits that they do not adapt all operating situations and circumstances such as design base events. In other words, these tools are only adapted foreseeable standardized operating situations and circumstances. In this study, our research team proposed an evidence-based approach such as UK's safety case to coping with the rare human error events such as TMI, Chernobyl, Fukushima accidents. These accidents are representative events involved with rare human errors. Our research team defined the 'rare human errors' as the follow three characterized events; Extremely low frequency Extremely high complicated structure Extremely serious damage of human life and property A safety case is a structured argument, supported by evidence, intended to justify that a system is acceptably safe. The definition by UK defense standard 00-56 issue 4 states that such an evidence-based approach can be contrast with a prescriptive approach to safety certification, which require safety to be justified using a prescribed process. Safety managements and safety regulatory activities based on safety case are effective to control organizational factors in terms of integrated safety management. Especially safety issues relevant with public acceptance are useful to provide practical evidences to the public reasonably. European Union including UK has developed the concept of engineered safety management system to deal with public acceptance using the safety case. In Korea nuclear industry, the Korean Atomic Research Institute has firstly performed a basic research to adapt the safety case in the field of radioactive waste according to the IAEA SSG-23(KAERI/TR-4497, 4531). Excepting the radioactive waste, there is no try to adapt the safety case yet. Most incidents and accidents involved human during operating NPPs have a tendency
How to Cope with the Rare Human Error Events Involved with organizational Factors in Nuclear Power Plants

International Nuclear Information System (INIS)

Kim, Sa Kil; Luo, Meiling; Lee, Yong Hee

2014-01-01

The current human error guidelines (e.g. US DOD handbooks, US NRC Guidelines) are representative tools to prevent human errors. These tools, however, have limits that they do not adapt all operating situations and circumstances such as design base events. In other words, these tools are only adapted foreseeable standardized operating situations and circumstances. In this study, our research team proposed an evidence-based approach such as UK's safety case to coping with the rare human error events such as TMI, Chernobyl, Fukushima accidents. These accidents are representative events involved with rare human errors. Our research team defined the 'rare human errors' as the follow three characterized events; Extremely low frequency Extremely high complicated structure Extremely serious damage of human life and property A safety case is a structured argument, supported by evidence, intended to justify that a system is acceptably safe. The definition by UK defense standard 00-56 issue 4 states that such an evidence-based approach can be contrast with a prescriptive approach to safety certification, which require safety to be justified using a prescribed process. Safety managements and safety regulatory activities based on safety case are effective to control organizational factors in terms of integrated safety management. Especially safety issues relevant with public acceptance are useful to provide practical evidences to the public reasonably. European Union including UK has developed the concept of engineered safety management system to deal with public acceptance using the safety case. In Korea nuclear industry, the Korean Atomic Research Institute has firstly performed a basic research to adapt the safety case in the field of radioactive waste according to the IAEA SSG-23(KAERI/TR-4497, 4531). Excepting the radioactive waste, there is no try to adapt the safety case yet. Most incidents and accidents involved human during operating NPPs have a tendency
Heart Failure: Diagnosis, Severity Estimation and Prediction of Adverse Events Through Machine Learning Techniques

Directory of Open Access Journals (Sweden)

Evanthia E. Tripoliti

Full Text Available Heart failure is a serious condition with high prevalence (about 2% in the adult population in developed countries, and more than 8% in patients older than 75 years. About 3–5% of hospital admissions are linked with heart failure incidents. Heart failure is the first cause of admission by healthcare professionals in their clinical practice. The costs are very high, reaching up to 2% of the total health costs in the developed countries. Building an effective disease management strategy requires analysis of large amount of data, early detection of the disease, assessment of the severity and early prediction of adverse events. This will inhibit the progression of the disease, will improve the quality of life of the patients and will reduce the associated medical costs. Toward this direction machine learning techniques have been employed. The aim of this paper is to present the state-of-the-art of the machine learning methodologies applied for the assessment of heart failure. More specifically, models predicting the presence, estimating the subtype, assessing the severity of heart failure and predicting the presence of adverse events, such as destabilizations, re-hospitalizations, and mortality are presented. According to the authors' knowledge, it is the first time that such a comprehensive review, focusing on all aspects of the management of heart failure, is presented. Keywords: Heart failure, Diagnosis, Prediction, Severity estimation, Classification, Data mining
Typhoid Fever Presenting With Acute Renal Failure And Hepatitis Simultaneously - A Rare Presentation

Directory of Open Access Journals (Sweden)

Rajput R.

2016-05-01

Full Text Available Typhoid fever is an important health problem worldwide but its incidence is more in developing countries. Hepatic involvement is common, but both hepatic and renal involvement is rare in typhoid fever. We report a case of typhoid fever presenting with hepatitis and acute renal failure. A 17 year old male presenting with fever and pain abdomen was found to have raised blood urea, creatinine, liver enzymes and bilirubin. Widal and typhidot (IgM,IgG test were positive. His symptoms subsided and deranged parameters resolved with treatment of typhoid fever.
Non-selective beta-blockers decrease thrombotic events in patients with heart failure

NARCIS (Netherlands)

De Peuter, Olav R.; Souverein, Patrick C.; Klungel, Olaf H.; Lip, Gregory Y.; Buller, Harry R.; De Boer, Anthonius; Kamphuisen, Pieter W.

2010-01-01

Background: Beta-blockers are often prescribed to patients with heart failure (HF) without distinctions between types of beta-blockers. The 2002 COMET study showed superiority of carvedilol (a non-selective beta-blocker) over metoprolol (selective beta-blocker) on mortality and cardiovascular events
Debugging Nondeterministic Failures in Linux Programs through Replay Analysis

Directory of Open Access Journals (Sweden)

Shakaiba Majeed

2018-01-01

Full Text Available Reproducing a failure is the first and most important step in debugging because it enables us to understand the failure and track down its source. However, many programs are susceptible to nondeterministic failures that are hard to reproduce, which makes debugging extremely difficult. We first address the reproducibility problem by proposing an OS-level replay system for a uniprocessor environment that can capture and replay nondeterministic events needed to reproduce a failure in Linux interactive and event-based programs. We then present an analysis method, called replay analysis, based on the proposed record and replay system to diagnose concurrency bugs in such programs. The replay analysis method uses a combination of static analysis, dynamic tracing during replay, and delta debugging to identify failure-inducing memory access patterns that lead to concurrency failure. The experimental results show that the presented record and replay system has low-recording overhead and hence can be safely used in production systems to catch rarely occurring bugs. We also present few concurrency bug case studies from real-world applications to prove the effectiveness of the proposed bug diagnosis framework.
ORGANIZATIONAL LEARNING IN RARE EVENTS: THE CASE OF LEARNING TO LITIGATE INTELLECTUAL PROPERTY (IP)

DEFF Research Database (Denmark)

Andersen, Kristina Vaarst; Beukel, Karin; Tyler, Beverly

This study proposes that firms can learn from previous litigations, despite litigation being a rare event. Firms learn because the verdicts are unambiguous and provide detailed and precise feedback on the linkages between argumentation, evidence and the outcome. Furthermore, firms’ successful app...
TaBoo SeArch Algorithm with a Modified Inverse Histogram for Reproducing Biologically Relevant Rare Events of Proteins.

Science.gov (United States)

Harada, Ryuhei; Takano, Yu; Shigeta, Yasuteru

2016-05-10

The TaBoo SeArch (TBSA) algorithm [ Harada et al. J. Comput. Chem. 2015 , 36 , 763 - 772 and Harada et al. Chem. Phys. Lett. 2015 , 630 , 68 - 75 ] was recently proposed as an enhanced conformational sampling method for reproducing biologically relevant rare events of a given protein. In TBSA, an inverse histogram of the original distribution, mapped onto a set of reaction coordinates, is constructed from trajectories obtained by multiple short-time molecular dynamics (MD) simulations. Rarely occurring states of a given protein are statistically selected as new initial states based on the inverse histogram, and resampling is performed by restarting the MD simulations from the new initial states to promote the conformational transition. In this process, the definition of the inverse histogram, which characterizes the rarely occurring states, is crucial for the efficiency of TBSA. In this study, we propose a simple modification of the inverse histogram to further accelerate the convergence of TBSA. As demonstrations of the modified TBSA, we applied it to (a) hydrogen bonding rearrangements of Met-enkephalin, (b) large-amplitude domain motions of Glutamine-Binding Protein, and (c) folding processes of the B domain of Staphylococcus aureus Protein A. All demonstrations numerically proved that the modified TBSA reproduced these biologically relevant rare events with nanosecond-order simulation times, although a set of microsecond-order, canonical MD simulations failed to reproduce the rare events, indicating the high efficiency of the modified TBSA.
Hypopituitarism presenting as congestive heart failure

Directory of Open Access Journals (Sweden)

S Giri

2017-01-01

Full Text Available Sheehan's syndrome (SS develops as a result of ischemic pituitary necrosis due to severe postpartum hemorrhage and is characterized by various degrees of hypopituitarism. Although the occurrence of SS is now rare, it should still be considered in any woman with a history of peripartum hemorrhage who develops manifestations of pituitary hormone deficiency any time following the event. Appropriate hormone replacement therapy results in marked clinical improvement. We present an unusual case of SS in a young lady who continued to have normal menstruation after the index event, had two spontaneous pregnancies, and was diagnosed only 11 years later when she presented to us with acute heart failure.
Neutron detector for detecting rare events of spontaneous fission

International Nuclear Information System (INIS)

Ter-Akop'yan, G.M.; Popeko, A.G.; Sokol, E.A.; Chelnokov, L.P.; Smirnov, V.I.; Gorshkov, V.A.

1981-01-01

The neutron detector for registering rare events of spontaneous fission by detecting multiple neutron emission is described. The detector represents a block of plexiglas of 550 mm diameter and 700 mm height in the centre of which there is a through 160 mm diameter channel for the sample under investigation. The detector comprises 56 3 He filled counters (up to 7 atm pressure) with 1% CO 2 addition. The counters have a 500 mm length and a 32 mm diameter. The sampling of fission events is realized by an electron system which allows determining the number of detected neutrons, numbers of operated counters, signal amplitude and time for fission event detecting. A block diagram of a neutron detector electron system is presented and its operation principle is considered. For protection against cosmic radiation the detector is surronded by a system of plastic scintillators and placed behind the concrete shield of 6 m thickness. The results of measurements of background radiation are given. It has been found that the background radiation of single neutron constitutes about 150 counts per hour, the detecting efficiency of single neutron equals 0.483 +- 0.005, for a 10l detector sensitive volume. By means of the detector described the parameters of multiplicity distribution of prompt neutrons for 256 Fm spontaneous fission are measured. The average multiplicity equals 3.59+-0.06 the dispersion being 2.30+-0.65
A Rare Case of Acute Renal Failure Secondary to Rhabdomyolysis Probably Induced by Donepezil

Directory of Open Access Journals (Sweden)

Osman Zikrullah Sahin

2014-01-01

Full Text Available Introduction. Acute renal failure (ARF develops in 33% of the patients with rhabdomyolysis. The main etiologic factors are alcoholism, trauma, exercise overexertion, and drugs. In this report we present a rare case of ARF secondary to probably donepezil-induced rhabdomyolysis. Case Presentation. An 84-year-old male patient was admitted to the emergency department with a complaint of generalized weakness and reduced consciousness for two days. He had a history of Alzheimer’s disease for one year and he had taken donepezil 5 mg daily for two months. The patient’s physical examination revealed apathy, loss of cooperation, and decreased muscle strength. Laboratory studies revealed the following: urea: 128 mg/dL; Creatinine 6.06 mg/dL; creatine kinase: 3613 mg/dL. Donepezil was discontinued and the patient’s renal function tests improved gradually. Conclusion. Rhabdomyolysis-induced acute renal failure may develop secondary to donepezil therapy.
When Siberia came to the Netherlands: The response of continental black-tailed godwits to a rare spring weather event

Science.gov (United States)

Senner, Nathan R.; Verhoeven, Mo A.; Abad-Gómez, José M.; Gutiérrez, Jorge S.; Hooijmeijer, Jos C. E. W.; Kentie, Rosemarie; Masero, José A.; Tibbitts, T. Lee; Piersma, Theunis

2015-01-01

Summary Extreme weather events have the potential to alter both short- and long-term population dynamics as well as community- and ecosystem-level function. Such events are rare and stochastic, making it difficult to fully document how organisms respond to them and predict the repercussions of similar events in the future.
Aspirin Does Not Increase Heart Failure Events in Heart Failure Patients: From the WARCEF Trial.

Science.gov (United States)

Teerlink, John R; Qian, Min; Bello, Natalie A; Freudenberger, Ronald S; Levin, Bruce; Di Tullio, Marco R; Graham, Susan; Mann, Douglas L; Sacco, Ralph L; Mohr, J P; Lip, Gregory Y H; Labovitz, Arthur J; Lee, Seitetz C; Ponikowski, Piotr; Lok, Dirk J; Anker, Stefan D; Thompson, John L P; Homma, Shunichi

2017-08-01

The aim of this study was to determine whether aspirin increases heart failure (HF) hospitalization or death in patients with HF with reduced ejection fraction receiving an angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB). Because of its cyclooxygenase inhibiting properties, aspirin has been postulated to increase HF events in patients treated with ACE inhibitors or ARBs. However, no large randomized trial has addressed the clinical relevance of this issue. We compared aspirin and warfarin for HF events (hospitalization, death, or both) in the 2,305 patients enrolled in the WARCEF (Warfarin versus Aspirin in Reduced Cardiac Ejection Fraction) trial (98.6% on ACE inhibitor or ARB treatment), using conventional Cox models for time to first event (489 events). In addition, to examine multiple HF hospitalizations, we used 2 extended Cox models, a conditional model and a total time marginal model, in time to recurrent event analyses (1,078 events). After adjustment for baseline covariates, aspirin- and warfarin-treated patients did not differ in time to first HF event (adjusted hazard ratio: 0.87; 95% confidence interval: 0.72 to 1.04; p = 0.117) or first hospitalization alone (adjusted hazard ratio: 0.88; 95% confidence interval: 0.73 to 1.06; p = 0.168). The extended Cox models also found no significant differences in all HF events or in HF hospitalizations alone after adjustment for covariates. Among patients with HF with reduced ejection fraction in the WARCEF trial, there was no significant difference in risk of HF events between the aspirin and warfarin-treated patients. (Warfarin Versus Aspirin in Reduced Cardiac Ejection Fraction trial [WARCEF]; NCT00041938). Copyright © 2017 American College of Cardiology Foundation. All rights reserved.
A Monte Carlo algorithm for sampling rare events: application to a search for the Griffiths singularity

International Nuclear Information System (INIS)

Hukushima, K; Iba, Y

2008-01-01

We develop a recently proposed importance-sampling Monte Carlo algorithm for sampling rare events and quenched variables in random disordered systems. We apply it to a two dimensional bond-diluted Ising model and study the Griffiths singularity which is considered to be due to the existence of rare large clusters. It is found that the distribution of the inverse susceptibility has an exponential tail down to the origin which is considered the consequence of the Griffiths singularity
Characterization of Rare Reverse Flow Events in Adverse Pressure Gradient Turbulent Boundary Layers

Science.gov (United States)

Kaehler, Christian J.; Bross, Matthew; Fuchs, Thomas

2017-11-01

Time-resolved tomographic flow fields measured in the viscous sublayer region of a turbulent boundary layer subjected to an adverse pressure gradient (APG) are examined with the aim to resolve and characterize reverse flow events at Reτ = 5000. The fields were measured using a novel high resolution tomographic particle tracking technique. It is shown that this technique is able to fully resolve mean and time dependent features of the complex three-dimensional flow with high accuracy down to very near-wall distances ( 10 μm). From time resolved Lagrangian particle trajectories, statistical information as well as instantaneous topological features of near-wall flow events are deduced. Similar to the zero pressure gradient case (ZPG), it was found that individual events with reverse flow components still occur relatively rarely under the action of the pressure gradient investigated here. However, reverse flow events comprised of many individual events, are shown to appear in relatively organized groupings in both spanwise and streamise directions. Furthermore, instantaneous measurements of reverse flow events show that these events are associated with the motion of low-momentum streaks in the near-wall region. This work is supported by the Priority Programme SPP 1881 Turbulent Superstructures and the individual project Grant KA1808/8-2 of the Deutsche Forschungsgemeinschaft.
Modeling the recurrent failure to thrive in less than two-year children: recurrent events survival analysis.

Science.gov (United States)

Saki Malehi, Amal; Hajizadeh, Ebrahim; Ahmadi, Kambiz; Kholdi, Nahid

2014-01-01

This study aimes to evaluate the failure to thrive (FTT) recurrent event over time. This longitudinal study was conducted during February 2007 to July 2009. The primary outcome was growth failure. The analysis was done using 1283 children who had experienced FTT several times, based on recurrent events analysis. Fifty-nine percent of the children had experienced the FTT at least one time and 5.3% of them had experienced it up to four times. The Prentice-Williams-Peterson (PWP) model revealed significant relationship between diarrhea (HR=1.26), respiratory infections (HR=1.25), urinary tract infections (HR=1.51), discontinuation of breast-feeding (HR=1.96), teething (HR=1.18), initiation age of complementary feeding (HR=1.11) and hazard rate of the first FTT event. Recurrence nature of the FTT is a main problem, which taking it into account increases the accuracy in analysis of FTT event process and can lead to identify different risk factors for each FTT recurrences.
Symptom-Hemodynamic Mismatch and Heart Failure Event Risk

Science.gov (United States)

Lee, Christopher S.; Hiatt, Shirin O.; Denfeld, Quin E.; Mudd, James O.; Chien, Christopher; Gelow, Jill M.

2014-01-01

Background Heart failure (HF) is a heterogeneous condition of both symptoms and hemodynamics. Objective The goal of this study was to identify distinct profiles among integrated data on physical and psychological symptoms and hemodynamics, and quantify differences in 180-day event-risk among observed profiles. Methods A secondary analysis of data collected during two prospective cohort studies by a single group of investigators was performed. Latent class mixture modeling was used to identify distinct symptom-hemodynamic profiles. Cox proportional hazards modeling was used to quantify difference in event-risk (HF emergency visit, hospitalization or death) among profiles. Results The mean age (n=291) was 57±13 years, 38% were female, and 61% had class III/IV HF. Three distinct symptom-hemodynamic profiles were identified. 17.9% of patients had concordant symptoms and hemodynamics (i.e. moderate physical and psychological symptoms matched the comparatively hemodynamic profile), 17.9% had severe symptoms and average hemodynamics, and 64.2% had poor hemodynamics and mild symptoms. Compared to those in the concordant profile, both profiles of symptom-hemodynamic mismatch were associated with a markedly increased event-risk (severe symptoms hazards ratio = 3.38, p=0.033; poor hemodynamics hazards ratio = 3.48, p=0.016). Conclusions A minority of adults with HF have concordant symptoms and hemodynamics. Either profile of symptom-hemodynamic mismatch in HF is associated with a greater risk of healthcare utilization for HF or death. PMID:24988323
FLARES: A flexible scintillation light apparatus for rare event searches

Energy Technology Data Exchange (ETDEWEB)

Sisti, M., E-mail: monica.sisti@mib.infn.it [Dipartimento di Fisica, Università di Milano-Bicocca and INFN – Sezione di Milano-Bicocca, Milano (Italy); Baldazzi, G. [Dipartimento di Fisica e Astronomia, Università di Bologna and INFN – Sezione di Bologna, Bologna (Italy); Bonvicini, V. [INFN – Sezione di Trieste, Trieste (Italy); Campana, R. [INAF/IASF and INFN – Sezione di Bologna, Bologna (Italy); Capelli, S. [Dipartimento di Fisica, Università di Milano-Bicocca and INFN – Sezione di Milano-Bicocca, Milano (Italy); Evangelista, Y.; Feroci, M. [INAF/IASF and INFN – Sezione di Roma2, Roma (Italy); Fuschino, F. [Dipartimento di Fisica e Astronomia, Università di Bologna and INFN – Sezione di Bologna, Bologna (Italy); INAF/IASF and INFN – Sezione di Bologna, Bologna (Italy); Gironi, L. [Dipartimento di Fisica, Università di Milano-Bicocca and INFN – Sezione di Milano-Bicocca, Milano (Italy); Labanti, C.; Marisaldi, M. [INAF/IASF and INFN – Sezione di Bologna, Bologna (Italy); Previtali, E. [Dipartimento di Fisica, Università di Milano-Bicocca and INFN – Sezione di Milano-Bicocca, Milano (Italy); Rignanese, L. [Dipartimento di Fisica e Astronomia, Università di Bologna and INFN – Sezione di Bologna, Bologna (Italy); Rachevsky, A. [INFN – Sezione di Trieste, Trieste (Italy); Vacchi, A. [INFN – Sezione di Trieste, Trieste (Italy); Dipartimento di Matematica e Informatica, Università di Udine, Udine (Italy); Zampa, G.; Zampa, N. [INFN – Sezione di Trieste, Trieste (Italy); Zuffa, M. [Dipartimento di Fisica e Astronomia, Università di Bologna and INFN – Sezione di Bologna, Bologna (Italy)

2016-07-11

FLARES is a project for an innovative detector technology to be applied to rare event searches, and in particular to neutrinoless double beta decay experiments. Its novelty is the enhancement and optimization of the collection of the scintillation light emitted by ultra-pure crystals through the use of arrays of high performance silicon photodetectors cooled to 120 K. This would provide scintillation detectors with 1% level energy resolution, with the advantages of a technology offering relatively simple low cost mass scalability and powerful background reduction handles, as requested by future neutrinoless double beta decay experimental programs. The performances of a first production of matrices of Silicon Drift Detectors are presented and discussed in this paper.

FLARES: A flexible scintillation light apparatus for rare event searches

International Nuclear Information System (INIS)

Sisti, M.; Baldazzi, G.; Bonvicini, V.; Campana, R.; Capelli, S.; Evangelista, Y.; Feroci, M.; Fuschino, F.; Gironi, L.; Labanti, C.; Marisaldi, M.; Previtali, E.; Rignanese, L.; Rachevsky, A.; Vacchi, A.; Zampa, G.; Zampa, N.; Zuffa, M.

2016-01-01

FLARES is a project for an innovative detector technology to be applied to rare event searches, and in particular to neutrinoless double beta decay experiments. Its novelty is the enhancement and optimization of the collection of the scintillation light emitted by ultra-pure crystals through the use of arrays of high performance silicon photodetectors cooled to 120 K. This would provide scintillation detectors with 1% level energy resolution, with the advantages of a technology offering relatively simple low cost mass scalability and powerful background reduction handles, as requested by future neutrinoless double beta decay experimental programs. The performances of a first production of matrices of Silicon Drift Detectors are presented and discussed in this paper.
Rare event computation in deterministic chaotic systems using genealogical particle analysis

International Nuclear Information System (INIS)

Wouters, J; Bouchet, F

2016-01-01

In this paper we address the use of rare event computation techniques to estimate small over-threshold probabilities of observables in deterministic dynamical systems. We demonstrate that genealogical particle analysis algorithms can be successfully applied to a toy model of atmospheric dynamics, the Lorenz ’96 model. We furthermore use the Ornstein–Uhlenbeck system to illustrate a number of implementation issues. We also show how a time-dependent objective function based on the fluctuation path to a high threshold can greatly improve the performance of the estimator compared to a fixed-in-time objective function. (paper)
Evaluation of common mode failure of safety functions for limiting fault events

International Nuclear Information System (INIS)

Rezendes, J.P.; Hyde, A.W.

2004-01-01

The draft U.S. Nuclear Regulatory Commission (NRC) policy on digital protection system software requires all Advanced Light Water Reactors (ALWRs) to be evaluated assuming a hypothetical common mode failure (CMF) which incapacitates the normal automatic initiation of safety functions. The System 80 + ALWR has been evaluated for such hypothetical conditions. The results show that the diverse automatic and manual protective systems in System 80 + provide ample safety performance margins relative to core coolability, offsite radiological releases. Reactor Coolant System (RCS) pressurization and containment integrity. This deterministic evaluation served to quantify the significant inherent safety margins in the System 80 + Standard Plant design even in the event of this extremely low probability scenario of a common mode failure. (author)
Financial system loss as an example of high consequence, high frequency events

Energy Technology Data Exchange (ETDEWEB)

McGovern, D.E.

1996-07-01

Much work has been devoted to high consequence events with low frequency of occurrence. Characteristic of these events are bridge failure (such as that of the Tacoma Narrows), building failure (such as the collapse of a walkway at a Kansas City hotel), or compromise of a major chemical containment system (such as at Bhopal, India). Such events, although rare, have an extreme personal, societal, and financial impact. An interesting variation is demonstrated by financial losses due to fraud and abuse in the money management system. The impact can be huge, entailing very high aggregate costs, but these are a result of the contribution of many small attacks and not the result of a single (or few) massive events. Public awareness is raised through publicized events such as the junk bond fraud perpetrated by Milikin or gross mismanagement in the failure of the Barings Bank through unsupervised trading activities by Leeson in Singapore. These event,s although seemingly large (financial losses may be on the order of several billion dollars), are but small contributors to the estimated $114 billion loss to all types of financial fraud in 1993. This paper explores the magnitude of financial system losses and identifies new areas for analysis of high consequence events including the potential effect of malevolent intent.
Medical costs in patients with heart failure after acute heart failure events: one-year follow-up study.

Science.gov (United States)

Kim, Eugene; Kwon, Hye-Young; Baek, Sang Hong; Lee, Haeyoung; Yoo, Byung-Su; Kang, Seok-Min; Ahn, Youngkeun; Yang, Bong-Min

2018-03-01

This study investigated annual medical costs using real-world data focusing on acute heart failure. The data were retrospectively collected from six tertiary hospitals in South Korea. Overall, 330 patients who were hospitalized for acute heart failure between January 2011 and July 2012 were selected. Data were collected on their follow-up medical visits for 1 year, including medical costs incurred toward treatment. Those who died within the observational period or who had no records of follow-up visits were excluded. Annual per patient medical costs were estimated according to the type of medical services, and factors contributing to the costs using Gamma Generalized Linear Models (GLM) with log link were analyzed. On average, total annual medical costs for each patient were USD 6,199 (±9,675), with hospitalization accounting for 95% of the total expenses. Hospitalization cost USD 5,904 (±9,666) per patient. Those who are re-admitted have 88.5% higher medical expenditure than those who have not been re-admitted in 1 year, and patients using intensive care units have 19.6% higher expenditure than those who do not. When the number of hospital days increased by 1 day, medical expenses increased by 6.7%. Outpatient drug costs were not included. There is a possibility that medical expenses for AHF may have been under-estimated. It was found that hospitalization resulted in substantial costs for treatment of heart failure in South Korea, especially in patients with an acute heart failure event. Prevention strategies and appropriate management programs that would reduce both frequency of hospitalization and length of stay for patients with the underlying risk of heart failure are needed.
Extreme events and predictability of catastrophic failure in composite materials and in the Earth

Science.gov (United States)

Main, I.; Naylor, M.

2012-05-01

Despite all attempts to isolate and predict extreme earthquakes, these nearly always occur without obvious warning in real time: fully deterministic earthquake prediction is very much a `black swan'. On the other hand engineering-scale samples of rocks and other composite materials often show clear precursors to dynamic failure under controlled conditions in the laboratory, and successful evacuations have occurred before several volcanic eruptions. This may be because extreme earthquakes are not statistically special, being an emergent property of the process of dynamic rupture. Nevertheless, probabilistic forecasting of event rate above a given size, based on the tendency of earthquakes to cluster in space and time, can have significant skill compared to say random failure, even in real-time mode. We address several questions in this debate, using examples from the Earth (earthquakes, volcanoes) and the laboratory, including the following. How can we identify `characteristic' events, i.e. beyond the power law, in model selection (do dragon-kings exist)? How do we discriminate quantitatively between stationary and non-stationary hazard models (is a dragon likely to come soon)? Does the system size (the size of the dragon's domain) matter? Are there localising signals of imminent catastrophic failure we may not be able to access (is the dragon effectively invisible on approach)? We focus on the effect of sampling effects and statistical uncertainty in the identification of extreme events and their predictability, and highlight the strong influence of scaling in space and time as an outstanding issue to be addressed by quantitative studies, experimentation and models.
CSNI group of experts on statistics and decision theories applicable to rare events. Final report may 1978 summary for presentation to the Garching meeting

International Nuclear Information System (INIS)

1978-01-01

The essential features of statistical techniques which are most useful for rare events may be grouped around four poles corresponding to four kinds of problems: decomposition of events and combination of probabilities; extrapolation (extreme values); Bayesian methods (and their relation with biased methods); dependencies (common modes). The main shadows, for the statistician point of view, are related to the confidence which can be attached to the data. Concerning rare events, much remains to be done in order to clarify the role and limits of efficiency of statistical methods. Recommendations are given: methods assembled by the group should be applied to different types of rare events encountered in nuclear safety; the necessary taking into account of the balance between the socio-economic advantages and potential drawbacks of nuclear technology
Neurological Respiratory Failure

Directory of Open Access Journals (Sweden)

Mohan Rudrappa

2018-01-01

Full Text Available West Nile virus infection in humans is mostly asymptomatic. Less than 1% of neuro-invasive cases show a fatality rate of around 10%. Acute flaccid paralysis of respiratory muscles leading to respiratory failure is the most common cause of death. Although the peripheral nervous system can be involved, isolated phrenic nerve palsy leading to respiratory failure is rare and described in only two cases in the English literature. We present another case of neurological respiratory failure due to West Nile virus-induced phrenic nerve palsy. Our case reiterates the rare, but lethal, consequences of West Nile virus infection, and the increase of its awareness among physicians.
Working group of experts on rare events in human error analysis and quantification

International Nuclear Information System (INIS)

Goodstein, L.P.

1977-01-01

In dealing with the reference problem of rare events in nuclear power plants, the group has concerned itself with the man-machine system and, in particular, with human error analysis and quantification. The Group was requested to review methods of human reliability prediction, to evaluate the extent to which such analyses can be formalized and to establish criteria to be met by task conditions and system design which would permit a systematic, formal analysis. Recommendations are given on the Fessenheim safety system
Merging expert and empirical data for rare event frequency estimation: Pool homogenisation for empirical Bayes models

International Nuclear Information System (INIS)

Quigley, John; Hardman, Gavin; Bedford, Tim; Walls, Lesley

2011-01-01

Empirical Bayes provides one approach to estimating the frequency of rare events as a weighted average of the frequencies of an event and a pool of events. The pool will draw upon, for example, events with similar precursors. The higher the degree of homogeneity of the pool, then the Empirical Bayes estimator will be more accurate. We propose and evaluate a new method using homogenisation factors under the assumption that events are generated from a Homogeneous Poisson Process. The homogenisation factors are scaling constants, which can be elicited through structured expert judgement and used to align the frequencies of different events, hence homogenising the pool. The estimation error relative to the homogeneity of the pool is examined theoretically indicating that reduced error is associated with larger pool homogeneity. The effects of misspecified expert assessments of the homogenisation factors are examined theoretically and through simulation experiments. Our results show that the proposed Empirical Bayes method using homogenisation factors is robust under different degrees of misspecification.
Analysis of events with common cause failures (CCF) from the international common cause failure date exchange (ICDE); Analyse von Ereignissen mit gemeinsam verursachten Ausfaellen (GVA) aus dem internationalen GVA-Datenaustauschprojekt ICDE

Energy Technology Data Exchange (ETDEWEB)

Brueck, Benjamin; Kreuser, Albert; Simon, Julia; Stiller, Jan

2014-08-15

Common-cause-failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. In recognition of this, CCF data are systematically being collected and analyzed in several countries. A comprehensive evaluation of CCF events derived only from the operating experience in German nuclear power plants is not sufficient due to the low probability of occurrence of such events. Therefore it is necessary to make use of the operating experience of other countries using similar technology. In order to be able to use the CCF operating experience from other countries in the aim to carry on the development of the bases for evaluation of CCF GRS decisively co-initiated the setting up of an international common-cause failure working group. This working group has elaborated the project ''International Common-Cause Failure Data Exchange'' (ICDE). The project's objective is to organize a broad exchange of information concerning observed events with relevance to common-cause failures. The tasks for preparation and evaluation of information of the ICDE working group serve for confirmation and extension of the common-cause failure knowledge with regards to probabilistic safety analyses, the better understanding of causes and mechanisms of common-cause failures and the evaluation of preventive measures against the occurrence of common-cause failures. The objectives of the exchange on a long term basis are to - improve the comprehension of CCF events and their causes and their prevention, - generate qualitative insights into the root causes of CCF events which can then be used to derive and assess preventive measures against the occurrence of such events or their consequences, - establish an efficient feedback of experience gained in connection with observed common-cause failure phenomena which could be used e.g. for the development of indicators for risk based inspections, - provide quantitative information regarding the
The Yusuf-Peto method was not a robust method for meta-analyses of rare events data from antidepressant trials

DEFF Research Database (Denmark)

Sharma, Tarang; Gøtzsche, Peter C.; Kuss, Oliver

2017-01-01

Objectives The aim of the study was to identify the validity of effect estimates for serious rare adverse events in clinical study reports of antidepressants trials, across different meta-analysis methods. Study Design and Setting Four serious rare adverse events (all-cause mortality, suicidality......, aggressive behavior, and akathisia) were meta-analyzed using different methods. The Yusuf-Peto odds ratio ignores studies with no events and was compared with the alternative approaches of generalized linear mixed models (GLMMs), conditional logistic regression, a Bayesian approach using Markov Chain Monte...... from 1. For example, the odds ratio for suicidality for children and adolescents was 2.39 (95% confidence interval = 1.32–4.33), using the Yusuf-Peto method but increased to 2.64 (1.33–5.26) using conditional logistic regression, to 2.69 (1.19–6.09) using beta-binomial, to 2.73 (1.37–5.42) using...
2004 Top 10 Chinese Rare Earth Events

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

1. Management to the Investment in Rare Earth IndustryConfirmedIn July 2004, "Decision on the Reform in Investment System" was formally publicized by the State Council of the People's Republic of China. The fifth item in the Decision stipulates that ore exploitation, smelting & separation and rare earth deep-processed projects with total investment over RMB￥100 million should be approved by the investment governing department of the State Council, and that other
Narrowing the scope of failure prediction using targeted fault load injection

Science.gov (United States)

Jordan, Paul L.; Peterson, Gilbert L.; Lin, Alan C.; Mendenhall, Michael J.; Sellers, Andrew J.

2018-05-01

As society becomes more dependent upon computer systems to perform increasingly critical tasks, ensuring that those systems do not fail becomes increasingly important. Many organizations depend heavily on desktop computers for day-to-day operations. Unfortunately, the software that runs on these computers is written by humans and, as such, is still subject to human error and consequent failure. A natural solution is to use statistical machine learning to predict failure. However, since failure is still a relatively rare event, obtaining labelled training data to train these models is not a trivial task. This work presents new simulated fault-inducing loads that extend the focus of traditional fault injection techniques to predict failure in the Microsoft enterprise authentication service and Apache web server. These new fault loads were successful in creating failure conditions that were identifiable using statistical learning methods, with fewer irrelevant faults being created.
Estimation Procedure of Common Cause Failure Parameters for CAFE-PSA

International Nuclear Information System (INIS)

Kang, Dae Il; Hwang, M. J.; Han, S. H.

2009-03-01

Detailed common cause failure (CCF) analysis generally needs the data for CCF events from other nuclear power plants because the CCF events rarely occur. Since 2002, KAERI has participated in the international common cause failure data exchange (ICDE) project to get data for CCF events. The operation office of the ICDE project sent about 400 CCF event data for emergency diesel generators, motor operated valves, check valves, pumps, and breakers to KAERI in 2009. However, there was no program available to analyze the ICDE CCF event data. Therefore, we developed the CAFE-PSA (common CAuse Failure Event analysis program for PSA) to estimate CCF parameters by using the ICDE CCF event data. With CAFE-PSA, the CCF events in the ICDE database can be qualitatively and quantitatively analyzed. The qualitative analysis results of the ICDE CCF data, by using the CAFE-PSA, showed that the major root cause of CCF events, for motor operated valves, check valves, and pumps, was the fault of their internal parts, and that for emergency diesel generators and breakers was the inadequacy of design/manufacture or construction. The quantitative analysis results of the ICDE CCF data, by using the CAFE-PSA, showed that the estimated Alpha Factors of components, mentioned above, were lower than those previously used in the PSA for domestic nuclear power plants, but were higher than those in USNRC 2007 CCF data. Through performing qualitative and quantitative analysis of the ICDE CCF data, by using the CAFE-PSA, a plan for coping with CCF events for design and operation of nuclear power plants can be produced and reasonable values for CCF parameters can be estimated. In addition, it is expected that the technical adequacy of PSA can be improved
Retrieval system for emplaced spent unreprocessed fuel (SURF) in salt bed depository: accident event analysis and mechanical failure probabilities. Final report

International Nuclear Information System (INIS)

Bhaskaran, G.; McCleery, J.E.

1979-10-01

This report provides support in developing an accident prediction event tree diagram, with an analysis of the baseline design concept for the retrieval of emplaced spent unreprocessed fuel (SURF) contained in a degraded Canister. The report contains an evaluation check list, accident logic diagrams, accident event tables, fault trees/event trees and discussions of failure probabilities for the following subsystems as potential contributors to a failure: (a) Canister extraction, including the core and ram units; (b) Canister transfer at the hoist area; and (c) Canister hoisting. This report is the second volume of a series. It continues and expands upon the report Retrieval System for Emplaced Spent Unreprocessed Fuel (SURF) in Salt Bed Depository: Baseline Concept Criteria Specifications and Mechanical Failure Probabilities. This report draws upon the baseline conceptual specifications contained in the first report
An infant with hyperalertness, hyperkinesis, and failure to thrive: a rare diencephalic syndrome due to hypothalamic anaplastic astrocytoma.

Science.gov (United States)

Stival, Alessia; Lucchesi, Maurizio; Farina, Silvia; Buccoliero, Anna Maria; Castiglione, Francesca; Genitori, Lorenzo; de Martino, Maurizio; Sardi, Iacopo

2015-09-04

Diencephalic Syndrome is a rare clinical condition of failure to thrive despite a normal caloric intake, hyperalertness, hyperkinesis, and euphoria usually associated with low-grade hypothalamic astrocytomas. We reported an unusual case of diencephalic cachexia due to hypothalamic anaplastic astrocytoma (WHO-grade III). Baseline endocrine function evaluation was performed in this patient before surgery. After histological diagnosis, he enrolled to a chemotherapy program with sequential high-dose chemotherapy followed by hematopoietic stem cell rescue. The last MRI evaluation showed a good response. The patient is still alive with good visual function 21 months after starting chemotherapy. Diencephalic cachexia can rarely be due to high-grade hypothalamic astrocytoma. We suggest that a nutritional support with chemotherapy given to high doses without radiotherapy could be an effective strategy for treatment of a poor-prognosis disease.
Rare recombination events generate sequence diversity among balancer chromosomes in Drosophila melanogaster.

Science.gov (United States)

Miller, Danny E; Cook, Kevin R; Yeganeh Kazemi, Nazanin; Smith, Clarissa B; Cockrell, Alexandria J; Hawley, R Scott; Bergman, Casey M

2016-03-08

Multiply inverted balancer chromosomes that suppress exchange with their homologs are an essential part of the Drosophila melanogaster genetic toolkit. Despite their widespread use, the organization of balancer chromosomes has not been characterized at the molecular level, and the degree of sequence variation among copies of balancer chromosomes is unknown. To map inversion breakpoints and study potential diversity in descendants of a structurally identical balancer chromosome, we sequenced a panel of laboratory stocks containing the most widely used X chromosome balancer, First Multiple 7 (FM7). We mapped the locations of FM7 breakpoints to precise euchromatic coordinates and identified the flanking sequence of breakpoints in heterochromatic regions. Analysis of SNP variation revealed megabase-scale blocks of sequence divergence among currently used FM7 stocks. We present evidence that this divergence arose through rare double-crossover events that replaced a female-sterile allele of the singed gene (sn(X2)) on FM7c with a sequence from balanced chromosomes. We propose that although double-crossover events are rare in individual crosses, many FM7c chromosomes in the Bloomington Drosophila Stock Center have lost sn(X2) by this mechanism on a historical timescale. Finally, we characterize the original allele of the Bar gene (B(1)) that is carried on FM7, and validate the hypothesis that the origin and subsequent reversion of the B(1) duplication are mediated by unequal exchange. Our results reject a simple nonrecombining, clonal mode for the laboratory evolution of balancer chromosomes and have implications for how balancer chromosomes should be used in the design and interpretation of genetic experiments in Drosophila.
Reactor pressure vessel failure probability following through-wall cracks due to pressurized thermal shock events

International Nuclear Information System (INIS)

Simonen, F.A.; Garnich, M.R.; Simonen, E.P.; Bian, S.H.; Nomura, K.K.; Anderson, W.E.; Pedersen, L.T.

1986-04-01

A fracture mechanics model was developed at the Pacific Northwest Laboratory (PNL) to predict the behavior of a reactor pressure vessel following a through-wall crack that occurs during a pressurized thermal shock (PTS) event. This study, which contributed to a US Nuclear Regulatory Commission (NRC) program to study PTS risk, was coordinated with the Integrated Pressurized Thermal Shock (IPTS) Program at Oak Ridge National Laboratory (ORNL). The PNL fracture mechanics model uses the critical transients and probabilities of through-wall cracks from the IPTS Program. The PNL model predicts the arrest, reinitiation, and direction of crack growth for a postulated through-wall crack and thereby predicts the mode of vessel failure. A Monte-Carlo type of computer code was written to predict the probabilities of the alternative failure modes. This code treats the fracture mechanics properties of the various welds and plates of a vessel as random variables. Plant-specific calculations were performed for the Oconee-1, Calvert Cliffs-1, and H.B. Robinson-2 reactor pressure vessels for the conditions of postulated transients. The model predicted that 50% or more of the through-wall axial cracks will turn to follow a circumferential weld. The predicted failure mode is a complete circumferential fracture of the vessel, which results in a potential vertically directed missile consisting of the upper head assembly. Missile arrest calculations for the three nuclear plants predict that such vertical missiles, as well as all potential horizontally directed fragmentation type missiles, will be confined to the vessel enclosre cavity. The PNL failure mode model is recommended for use in future evaluations of other plants, to determine the failure modes that are most probable for postulated PTS events
Pattern of failure following surgical resection of renal cell carcinoma

International Nuclear Information System (INIS)

Aref, I.; Bociek, G.; Salhani, D.

1996-01-01

Purpose/objective: To identify the pattern of failure in patients with resected renal cell carcinoma (RCC). Materials and Methods: The records of 116 patients with unilateral non-metastatic RCC, who were treated with definitive surgery and referred to the Ottawa Regional Cancer Centre between 1977 and 1988, were reviewed. Distribution by stage included: T1 = 3 patients, T2 = 42 patients, T3 =71 patients. The median follow-up was 44 months, with a range of 4-267 months. Results: Loco-regional failure (LRF) developed in 8 patients, yielding a 7-year actuarial incidence of 8% for LRF, as first event. Nine patients developed local or regional recurrence + distant failure, and 58 patients had distant metastases only. Seven-year actuarial incidence of distant failure was 55%. The overall 7-year actuarial survival rate was 40%, and cause-specific survival was 45%. Conclusion: LRF was rare following nephrectomy. This data does not support the role of adjuvant radiation therapy in this disease

Immunoadjuvant Therapy and Noninvasive Ventilation for Acute Respiratory Failure in Lung Tuberculosis: A Case Study

Directory of Open Access Journals (Sweden)

René Agustín Flores-Franco

2015-01-01

Full Text Available Acute respiratory failure caused by pulmonary tuberculosis is a rare event but with a high mortality even while receiving mechanical ventilatory support. We report the case of a young man with severe pulmonary tuberculosis refractory to conventional therapy who successfully overcame the critical period of his condition using noninvasive ventilation and immunoadjuvant therapy that included three doses of etanercept 25 mg subcutaneously. We conclude that the use of etanercept along with antituberculosis treatment appears to be safe and effective in patients with pulmonary tuberculosis presenting with acute respiratory failure.
Undetected latent failures of safety-related systems. Preliminary survey of events in nuclear power plants 1980-1997

International Nuclear Information System (INIS)

Lydell, B.

1998-03-01

This report summarizes results and insights from a preliminary survey of events involving undetected, latent failures of safety-related systems. The survey was limited to events where mispositioned equipment (e.g., valves, switches) remained undetected, thus rendering standby equipment or systems unavailable for short or long time periods. Typically, these events were symptoms of underlying latent errors (e.g., design errors, procedure errors, unanalyzed safety conditions) and programmatic errors. The preliminary survey identified well over 300 events. Of these, 95 events are documented in this report. Events involving mispositioned equipment are commonplace. Most events are discovered soon after occurrence, however. But as evidenced by the survey results, some events remained undetected beyond several shift changes. The recommendations developed by the survey emphasize the importance of applying modern root cause analysis techniques to the event analysis to ensure that the causes and implications of occurred events are fully understood
Determination of point of maximum likelihood in failure domain using genetic algorithms

International Nuclear Information System (INIS)

Obadage, A.S.; Harnpornchai, N.

2006-01-01

The point of maximum likelihood in a failure domain yields the highest value of the probability density function in the failure domain. The maximum-likelihood point thus represents the worst combination of random variables that contribute in the failure event. In this work Genetic Algorithms (GAs) with an adaptive penalty scheme have been proposed as a tool for the determination of the maximum likelihood point. The utilization of only numerical values in the GAs operation makes the algorithms applicable to cases of non-linear and implicit single and multiple limit state function(s). The algorithmic simplicity readily extends its application to higher dimensional problems. When combined with Monte Carlo Simulation, the proposed methodology will reduce the computational complexity and at the same time will enhance the possibility in rare-event analysis under limited computational resources. Since, there is no approximation done in the procedure, the solution obtained is considered accurate. Consequently, GAs can be used as a tool for increasing the computational efficiency in the element and system reliability analyses
Importance sampling of rare events in chaotic systems

DEFF Research Database (Denmark)

Leitão, Jorge C.; Parente Lopes, João M.Viana; Altmann, Eduardo G.

2017-01-01

space of chaotic systems. As examples of our general framework we compute the distribution of finite-time Lyapunov exponents (in different chaotic maps) and the distribution of escape times (in transient-chaos problems). Our methods sample exponentially rare states in polynomial number of samples (in......Finding and sampling rare trajectories in dynamical systems is a difficult computational task underlying numerous problems and applications. In this paper we show how to construct Metropolis-Hastings Monte-Carlo methods that can efficiently sample rare trajectories in the (extremely rough) phase...... both low- and high-dimensional systems). An open-source software that implements our algorithms and reproduces our results can be found in reference [J. Leitao, A library to sample chaotic systems, 2017, https://github.com/jorgecarleitao/chaospp]....
Event group importance measures for top event frequency analyses

International Nuclear Information System (INIS)

1995-01-01

Three traditional importance measures, risk reduction, partial derivative, nd variance reduction, have been extended to permit analyses of the relative importance of groups of underlying failure rates to the frequencies of resulting top events. The partial derivative importance measure was extended by assessing the contribution of a group of events to the gradient of the top event frequency. Given the moments of the distributions that characterize the uncertainties in the underlying failure rates, the expectation values of the top event frequency, its variance, and all of the new group importance measures can be quantified exactly for two familiar cases: (1) when all underlying failure rates are presumed independent, and (2) when pairs of failure rates based on common data are treated as being equal (totally correlated). In these cases, the new importance measures, which can also be applied to assess the importance of individual events, obviate the need for Monte Carlo sampling. The event group importance measures are illustrated using a small example problem and demonstrated by applications made as part of a major reactor facility risk assessment. These illustrations and applications indicate both the utility and the versatility of the event group importance measures
Event group importance measures for top event frequency analyses

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-31

Three traditional importance measures, risk reduction, partial derivative, nd variance reduction, have been extended to permit analyses of the relative importance of groups of underlying failure rates to the frequencies of resulting top events. The partial derivative importance measure was extended by assessing the contribution of a group of events to the gradient of the top event frequency. Given the moments of the distributions that characterize the uncertainties in the underlying failure rates, the expectation values of the top event frequency, its variance, and all of the new group importance measures can be quantified exactly for two familiar cases: (1) when all underlying failure rates are presumed independent, and (2) when pairs of failure rates based on common data are treated as being equal (totally correlated). In these cases, the new importance measures, which can also be applied to assess the importance of individual events, obviate the need for Monte Carlo sampling. The event group importance measures are illustrated using a small example problem and demonstrated by applications made as part of a major reactor facility risk assessment. These illustrations and applications indicate both the utility and the versatility of the event group importance measures.
A mid-layer model for human reliability analysis: understanding the cognitive causes of human failure events

International Nuclear Information System (INIS)

Shen, Song-Hua; Chang, James Y.H.; Boring, Ronald L.; Whaley, April M.; Lois, Erasmia; Langfitt Hendrickson, Stacey M.; Oxstrand, Johanna H.; Forester, John Alan; Kelly, Dana L.; Mosleh, Ali

2010-01-01

The Office of Nuclear Regulatory Research (RES) at the US Nuclear Regulatory Commission (USNRC) is sponsoring work in response to a Staff Requirements Memorandum (SRM) directing an effort to establish a single human reliability analysis (HRA) method for the agency or guidance for the use of multiple methods. As part of this effort an attempt to develop a comprehensive HRA qualitative approach is being pursued. This paper presents a draft of the method's middle layer, a part of the qualitative analysis phase that links failure mechanisms to performance shaping factors. Starting with a Crew Response Tree (CRT) that has identified human failure events, analysts identify potential failure mechanisms using the mid-layer model. The mid-layer model presented in this paper traces the identification of the failure mechanisms using the Information-Diagnosis/Decision-Action (IDA) model and cognitive models from the psychological literature. Each failure mechanism is grouped according to a phase of IDA. Under each phase of IDA, the cognitive models help identify the relevant performance shaping factors for the failure mechanism. The use of IDA and cognitive models can be traced through fault trees, which provide a detailed complement to the CRT.
A Mid-Layer Model for Human Reliability Analysis: Understanding the Cognitive Causes of Human Failure Events

Energy Technology Data Exchange (ETDEWEB)

Stacey M. L. Hendrickson; April M. Whaley; Ronald L. Boring; James Y. H. Chang; Song-Hua Shen; Ali Mosleh; Johanna H. Oxstrand; John A. Forester; Dana L. Kelly; Erasmia L. Lois

2010-06-01

The Office of Nuclear Regulatory Research (RES) is sponsoring work in response to a Staff Requirements Memorandum (SRM) directing an effort to establish a single human reliability analysis (HRA) method for the agency or guidance for the use of multiple methods. As part of this effort an attempt to develop a comprehensive HRA qualitative approach is being pursued. This paper presents a draft of the method’s middle layer, a part of the qualitative analysis phase that links failure mechanisms to performance shaping factors. Starting with a Crew Response Tree (CRT) that has identified human failure events, analysts identify potential failure mechanisms using the mid-layer model. The mid-layer model presented in this paper traces the identification of the failure mechanisms using the Information-Diagnosis/Decision-Action (IDA) model and cognitive models from the psychological literature. Each failure mechanism is grouped according to a phase of IDA. Under each phase of IDA, the cognitive models help identify the relevant performance shaping factors for the failure mechanism. The use of IDA and cognitive models can be traced through fault trees, which provide a detailed complement to the CRT.
Sacubitril and valsartan fixed combination to reduce heart failure events in post-acute myocardial infarction patients.

Science.gov (United States)

Zaid Iskandar, M; Lang, C C

2017-10-01

Heart failure is a term used to define a constellation of symptoms and signs that are commonly attributed to the inability of the heart to produce a cardiac output that meets the demands of the body. It remains a deadly disease, affecting between 1-2% of the population, and is more common in the elderly, with around 6-10% of patients over 65 suffering from the condition. Sacubitril/valsartan (LCZ-696) is a combined neprilysin inhibitor and angiotensin AT1 receptor blocker approved in recent years for the treatment of chronic heart failure with reduced ejection fraction. In an area where there have been limited pharmacological advances in the last 10 years, this drug was a game changer and a much welcomed addition to contemporary heart failure therapy. It is currently being studied in patients with heart failure with preserved ejection fraction and for the reduction of heart failure events post-acute myocardial infarction. Results from the ongoing PARADISE-MI study are awaited by the global cardiology community with great interest. Copyright 2017 Clarivate Analytics.
Event-triggered decentralized adaptive fault-tolerant control of uncertain interconnected nonlinear systems with actuator failures.

Science.gov (United States)

Choi, Yun Ho; Yoo, Sung Jin

2018-06-01

This paper investigates the event-triggered decentralized adaptive tracking problem of a class of uncertain interconnected nonlinear systems with unexpected actuator failures. It is assumed that local control signals are transmitted to local actuators with time-varying faults whenever predefined conditions for triggering events are satisfied. Compared with the existing control-input-based event-triggering strategy for adaptive control of uncertain nonlinear systems, the aim of this paper is to propose a tracking-error-based event-triggering strategy in the decentralized adaptive fault-tolerant tracking framework. The proposed approach can relax drastic changes in control inputs caused by actuator faults in the existing triggering strategy. The stability of the proposed event-triggering control system is analyzed in the Lyapunov sense. Finally, simulation comparisons of the proposed and existing approaches are provided to show the effectiveness of the proposed theoretical result in the presence of actuator faults. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.
Undetected latent failures of safety-related systems. Preliminary survey of events in nuclear power plants 1980-1997

Energy Technology Data Exchange (ETDEWEB)

Lydell, B. [RSA Technologies, Vista, CA (United States)

1998-03-01

This report summarizes results and insights from a preliminary survey of events involving undetected, latent failures of safety-related systems. The survey was limited to events where mispositioned equipment (e.g., valves, switches) remained undetected, thus rendering standby equipment or systems unavailable for short or long time periods. Typically, these events were symptoms of underlying latent errors (e.g., design errors, procedure errors, unanalyzed safety conditions) and programmatic errors. The preliminary survey identified well over 300 events. Of these, 95 events are documented in this report. Events involving mispositioned equipment are commonplace. Most events are discovered soon after occurrence, however. But as evidenced by the survey results, some events remained undetected beyond several shift changes. The recommendations developed by the survey emphasize the importance of applying modern root cause analysis techniques to the event analysis to ensure that the causes and implications of occurred events are fully understood. 7 refs, 4 tabs, 3 figs. Also available at the SKI Home page: //www.ski.se.
Data bank international of events of failure of common cause ICDE; Banco de datos internacional de sucesos de fallo de causa comum (ICDE)

Energy Technology Data Exchange (ETDEWEB)

Morales Castellanos, M. R.; Fernandez Andujar, B.; Pereira Pagan, M. B.

2013-07-01

Common Cause Failure (CCF) is a dependent event in which two or more components fail simultaneously or within a short space of time as a direct result of a shared common cause. Due to the low frequency of this type of events, some Member States of the Agency of Nuclear Energy (NEA) of the Organization for Cooperation and Economic Development (OECD) decided to create the project International Common-Cause Failure Data Exchange (ICDE) in order to encourage multilateral cooperation in the collection and analysis of data relating to CCF events.
Non-compaction cardiomyopathy – an unusual cause of heart failure

Directory of Open Access Journals (Sweden)

Jure Dolenc

2011-03-01

Full Text Available Introduction: Non-compaction cardiomyopathy is a rare inborn anomaly caused by disorder of endomyocardial morphogenesis. The diagnosis is based on echocardiographic criteria. The prevalence in the adult population is not known. The symptoms are atypical. Three main groups of clinical signs exist: heart failure, thromobembolic events and arrhythmias. In the group of patients with reduced left ventricular function the prognosis is poor and the treatment options are limited. Patients and methods: In the recent 10 years, 7 patients with non-compaction cardiomyopathy were diagnosed at the Department of Cardiology of the University Medical Centre Ljubljana. Results: All seven patients were males, their mean age at the last follow-up being 39 ± 20.3 years (range 20 to 70 years. Five patients were diagnosed in adulthood. All of them fulfilled the echocardiographic diagnostic criteria of noncompaction cardiomyopathy. Five patients had depressed function of both ventricles, two patients had isolated left ventricular dysfunction. Three patients had decreased left ventricular ejection fraction, six patients showed left ventricular diastolic dysfunction. Only three patients had normal physical capacity. Two patients presented with clinical signs of overt heart failure. During follow-up, one patient died from heart failure. We observed thromboembolic events in one patient. Three patients suffered from nonsustained ventricular tachycardias and two patients had rhythm conduction abnormalities. Conclusions: Non-compaction cardiomyopathy is a rare disorder. We observed all common complications in our group of patients. The majority of patients displayed dysfunction of the affected ventricle and the dysfunction was more pronounced in older patients. Treatment of complications is an important factor in long-term survival of these patients.
Enhancing Important Fluctuations: Rare Events and Metadynamics from a Conceptual Viewpoint

Science.gov (United States)

Valsson, Omar; Tiwary, Pratyush; Parrinello, Michele

2016-05-01

Atomistic simulations play a central role in many fields of science. However, their usefulness is often limited by the fact that many systems are characterized by several metastable states separated by high barriers, leading to kinetic bottlenecks. Transitions between metastable states are thus rare events that occur on significantly longer timescales than one can simulate in practice. Numerous enhanced sampling methods have been introduced to alleviate this timescale problem, including methods based on identifying a few crucial order parameters or collective variables and enhancing the sampling of these variables. Metadynamics is one such method that has proven successful in a great variety of fields. Here we review the conceptual and theoretical foundations of metadynamics. As demonstrated, metadynamics is not just a practical tool but can also be considered an important development in the theory of statistical mechanics.
Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

Science.gov (United States)

Chevuturi, A.; Dimri, A. P.; Gunturu, U. B.

2014-12-01

This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00-18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.
Numerical simulation of a rare winter hailstorm event over Delhi, India on 17 January 2013

KAUST Repository

Chevuturi, A.

2014-12-19

This study analyzes the cause of the rare occurrence of a winter hailstorm over New Delhi/NCR (National Capital Region), India. The absence of increased surface temperature or low level of moisture incursion during winter cannot generate the deep convection required for sustaining a hailstorm. Consequently, NCR shows very few cases of hailstorms in the months of December-January-February, making the winter hail formation a question of interest. For this study, a recent winter hailstorm event on 17 January 2013 (16:00–18:00 UTC) occurring over NCR is investigated. The storm is simulated using the Weather Research and Forecasting (WRF) model with the Goddard Cumulus Ensemble (GCE) microphysics scheme with two different options: hail and graupel. The aim of the study is to understand and describe the cause of hailstorm event during over NCR with a comparative analysis of the two options of GCE microphysics. Upon evaluating the model simulations, it is observed that the hail option shows a more similar precipitation intensity with the Tropical Rainfall Measuring Mission (TRMM) observation than the graupel option does, and it is able to simulate hail precipitation. Using the model-simulated output with the hail option; detailed investigation on understanding the dynamics of hailstorm is performed. The analysis based on a numerical simulation suggests that the deep instability in the atmospheric column led to the formation of hailstones as the cloud formation reached up to the glaciated zone promoting ice nucleation. In winters, such instability conditions rarely form due to low level available potential energy and moisture incursion along with upper level baroclinic instability due to the presence of a western disturbance (WD). Such rare positioning is found to be lowering the tropopause with increased temperature gradient, leading to winter hailstorm formation.
Uncertainty analysis with statistically correlated failure data

International Nuclear Information System (INIS)

Modarres, M.; Dezfuli, H.; Roush, M.L.

1987-01-01

Likelihood of occurrence of the top event of a fault tree or sequences of an event tree is estimated from the failure probability of components that constitute the events of the fault/event tree. Component failure probabilities are subject to statistical uncertainties. In addition, there are cases where the failure data are statistically correlated. At present most fault tree calculations are based on uncorrelated component failure data. This chapter describes a methodology for assessing the probability intervals for the top event failure probability of fault trees or frequency of occurrence of event tree sequences when event failure data are statistically correlated. To estimate mean and variance of the top event, a second-order system moment method is presented through Taylor series expansion, which provides an alternative to the normally used Monte Carlo method. For cases where component failure probabilities are statistically correlated, the Taylor expansion terms are treated properly. Moment matching technique is used to obtain the probability distribution function of the top event through fitting the Johnson Ssub(B) distribution. The computer program, CORRELATE, was developed to perform the calculations necessary for the implementation of the method developed. (author)
Incidence of patient safety events and process-related human failures during intra-hospital transportation of patients: retrospective exploration from the institutional incident reporting system.

Science.gov (United States)

Yang, Shu-Hui; Jerng, Jih-Shuin; Chen, Li-Chin; Li, Yu-Tsu; Huang, Hsiao-Fang; Wu, Chao-Ling; Chan, Jing-Yuan; Huang, Szu-Fen; Liang, Huey-Wen; Sun, Jui-Sheng

2017-11-03

Intra-hospital transportation (IHT) might compromise patient safety because of different care settings and higher demand on the human operation. Reports regarding the incidence of IHT-related patient safety events and human failures remain limited. To perform a retrospective analysis of IHT-related events, human failures and unsafe acts. A hospital-wide process for the IHT and database from the incident reporting system in a medical centre in Taiwan. All eligible IHT-related patient safety events between January 2010 to December 2015 were included. Incidence rate of IHT-related patient safety events, human failure modes, and types of unsafe acts. There were 206 patient safety events in 2 009 013 IHT sessions (102.5 per 1 000 000 sessions). Most events (n=148, 71.8%) did not involve patient harm, and process events (n=146, 70.9%) were most common. Events at the location of arrival (n=101, 49.0%) were most frequent; this location accounted for 61.0% and 44.2% of events with patient harm and those without harm, respectively (pprocess step was the preparation of the transportation team (n=91, 48.9%). Contributing unsafe acts included perceptual errors (n=14, 7.5%), decision errors (n=56, 30.1%), skill-based errors (n=48, 25.8%), and non-compliance (n=68, 36.6%). Multivariate analysis showed that human failure found in the arrival and hand-off sub-process (OR 4.84, pprocess at the location of arrival and prevent errors other than omissions. Long-term monitoring of IHT-related events is also warranted. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Two loose screws: near-miss fall of a morbidly obese patient after an operating room table failure.

Science.gov (United States)

McAllister, Russell K; Booth, Robert T; Bittenbinder, Timothy M

2016-09-01

Operating room surgical table failure is a rare event but can lead to a dangerous situation when it does occur. The dangers can be compounded in the presence of obesity, especially in the anesthetized or sedated patient. We present a case of a near-miss fall of a morbidly obese patient while turning the patient in preparation to transfer from the operating room table to the hospital bed when 2 fractured bolts in the tilt cylinder mechanism led to an operating room table failure. Copyright © 2016 Elsevier Inc. All rights reserved.
Heart failure as an endpoint in heart failure and non-heart failure cardiovascular clinical trials: the need for a consensus definition

DEFF Research Database (Denmark)

Zannad, F.; Stough, W.G.; Pitt, B.

2008-01-01

Specific criteria have been established to define the occurrence of myocardial infarction (MI) and stroke in cardiovascular clinical trials, but there is not a consistent definition for heart failure. Heart failure events appear to occur at a rate that is similar to stroke and MI in trials...... of hypertension, hyperlipidaemia, diabetes, and coronary heart disease, yet a consistent approach to defining heart failure events has not yet been realized. The wide range of definitions used in clinical trials makes it difficult to interpret new data in the context of existing literature. This inconsistency has...... led to challenges in determining the incidence of heart failure in cardiovascular studies and the effects of interventions on these endpoints. This paper examines issues related to defining heart failure events in cardiovascular clinical trials and presents a definition to formally address this issue...

A Dynamic Approach to Modeling Dependence Between Human Failure Events

Energy Technology Data Exchange (ETDEWEB)

Boring, Ronald Laurids [Idaho National Laboratory

2015-09-01

In practice, most HRA methods use direct dependence from THERP—the notion that error be- gets error, and one human failure event (HFE) may increase the likelihood of subsequent HFEs. In this paper, we approach dependence from a simulation perspective in which the effects of human errors are dynamically modeled. There are three key concepts that play into this modeling: (1) Errors are driven by performance shaping factors (PSFs). In this context, the error propagation is not a result of the presence of an HFE yielding overall increases in subsequent HFEs. Rather, it is shared PSFs that cause dependence. (2) PSFs have qualities of lag and latency. These two qualities are not currently considered in HRA methods that use PSFs. Yet, to model the effects of PSFs, it is not simply a matter of identifying the discrete effects of a particular PSF on performance. The effects of PSFs must be considered temporally, as the PSFs will have a range of effects across the event sequence. (3) Finally, there is the concept of error spilling. When PSFs are activated, they not only have temporal effects but also lateral effects on other PSFs, leading to emergent errors. This paper presents the framework for tying together these dynamic dependence concepts.
Study of 'inadvertent human intrusion or rare natural event scenarios' for sub-surface disposal of radioactive waste

International Nuclear Information System (INIS)

Nakatani, Takayoshi; Ishitoya, Kimihide; Funabashi, Hideyuki; Sugaya, Toshikatsu; Sone, Tomoyuki; Shimada, Hidemitsu; Nakai, Kunihiro

2010-03-01

Japan Atomic Energy Agency (JAEA) is making preparations for the sub-surface disposal of radioactive wastes, in an integrated fashion according to the properties of the waste material regardless of the generators or waste sources. In this study, 'Inadvertent Human Intrusion or Rare Natural Event Scenarios' of 'Three Types scenarios' was considered according to the standard of the Atomic Energy Society of Japan (AESJ) on the sub-surface disposal system that was based on 'Basic Policy for Safety Regulation Concerning Land Disposal of Low-Level Radioactive Waste (Interim Report)' by Nuclear Safety Commission of Japan (NSC). Selection of the assessed scenarios, development of the assessment tool and preliminary exposure dose assessment for general public were conducted. Among the assessed scenarios, the exposure dose of 'well water drinking scenario' was the highest under the very conservative assessment condition. This scenario assumed that the groundwater in Excavation Disturbed Zone (EDZ) was directly used as drinking water without any dilution. Although this was very conservative condition and the result exceeded 10 mSv/y, it stayed under the upper limit of standard dose value for 'Inadvertent Human Intrusion or Rare Natural Event Scenarios' (10 - 100 mSv/y). (author)
Characterization of polyethylene terephthalate (PET) detector to search for rare events in cosmic rays

International Nuclear Information System (INIS)

Dey, S.; Maulik, A.; Raha, Sibaji; Sara, Swapan; Syam, D.

2015-01-01

A particular brand of commercially available plastic, identified as polyethylene terephthalate (PET) has been used as a Nuclear Track Detector (NTD) to detect heavy charged particles. It was found that PET has a much higher detection threshold compared to other commercially available NTDs, making PET particularly suitable for detecting rare events in cosmic rays. To characterize and calibrate PET, systemetic studies were carried out using ions from various accelerators in India and Europe. Results of those studies have shown that PET can be effectively used as a charge particle detector with good energy and charge resolution. (author)
Cosmogenic activation of germanium used for tonne-scale rare event search experiments

Science.gov (United States)

Wei, W.-Z.; Mei, D.-M.; Zhang, C.

2017-11-01

We report a comprehensive study of cosmogenic activation of germanium used for tonne-scale rare event search experiments. The germanium exposure to cosmic rays on the Earth's surface are simulated with and without a shielding container using Geant4 for a given cosmic muon, neutron, and proton energy spectrum. The production rates of various radioactive isotopes are obtained for different sources separately. We find that fast neutron induced interactions dominate the production rate of cosmogenic activation. Geant4-based simulation results are compared with the calculation of ACTIVIA and the available experimental data. A reasonable agreement between Geant4 simulations and several experimental data sets is presented. We predict that cosmogenic activation of germanium can set limits to the sensitivity of the next generation of tonne-scale experiments.
Amenorrhea as a rare drug-related adverse event associated with everolimus for pancreatic neuroendocrine tumors.

Science.gov (United States)

Kawaguchi, Yoshiaki; Maruno, Atsuko; Kawashima, Yohei; Ito, Hiroyuki; Ogawa, Masami; Mine, Tetsuya

2014-11-14

The patient was an asymptomatic 43-year-old woman. Abdominal ultrasonography and enhanced computed tomography showed a tumor lesion accompanied by multiple cystic changes in the liver and the pancreatic tail. Endoscopic ultrasound-fine needle aspiration was performed on the pancreatic tumor lesion and revealed pancreatic neuroendocrine tumor (PNET). As it was unresectable due to multiple liver metastases, the decision was made to initiate treatment with everolimus and transcatheter arterial chemoembolization. The patient ceased menstruating after the start of everolimus administration. When the administration was discontinued due to interstitial lung disease, menstruation resumed, but then again stopped with everolimus resumption. An association between everolimus and amenorrhea was highly suspected. Amenorrhea occurred as a rare adverse event of everolimus. As the younger women might be included in PNETs patients, we should put this adverse event into consideration.
Dependent failure analysis of NPP data bases

International Nuclear Information System (INIS)

Cooper, S.E.; Lofgren, E.V.; Samanta, P.K.; Wong Seemeng

1993-01-01

A technical approach for analyzing plant-specific data bases for vulnerabilities to dependent failures has been developed and applied. Since the focus of this work is to aid in the formulation of defenses to dependent failures, rather than to quantify dependent failure probabilities, the approach of this analysis is critically different. For instance, the determination of component failure dependencies has been based upon identical failure mechanisms related to component piecepart failures, rather than failure modes. Also, component failures involving all types of component function loss (e.g., catastrophic, degraded, incipient) are equally important to the predictive purposes of dependent failure defense development. Consequently, dependent component failures are identified with a different dependent failure definition which uses a component failure mechanism categorization scheme in this study. In this context, clusters of component failures which satisfy the revised dependent failure definition are termed common failure mechanism (CFM) events. Motor-operated valves (MOVs) in two nuclear power plant data bases have been analyzed with this approach. The analysis results include seven different failure mechanism categories; identified potential CFM events; an assessment of the risk-significance of the potential CFM events using existing probabilistic risk assessments (PRAs); and postulated defenses to the identified potential CFM events. (orig.)
Multiscale models and stochastic simulation methods for computing rare but key binding events in cell biology

Energy Technology Data Exchange (ETDEWEB)

Guerrier, C. [Applied Mathematics and Computational Biology, IBENS, Ecole Normale Supérieure, 46 rue d' Ulm, 75005 Paris (France); Holcman, D., E-mail: david.holcman@ens.fr [Applied Mathematics and Computational Biology, IBENS, Ecole Normale Supérieure, 46 rue d' Ulm, 75005 Paris (France); Mathematical Institute, Oxford OX2 6GG, Newton Institute (United Kingdom)

2017-07-01

The main difficulty in simulating diffusion processes at a molecular level in cell microdomains is due to the multiple scales involving nano- to micrometers. Few to many particles have to be simulated and simultaneously tracked while there are exploring a large portion of the space for binding small targets, such as buffers or active sites. Bridging the small and large spatial scales is achieved by rare events representing Brownian particles finding small targets and characterized by long-time distribution. These rare events are the bottleneck of numerical simulations. A naive stochastic simulation requires running many Brownian particles together, which is computationally greedy and inefficient. Solving the associated partial differential equations is also difficult due to the time dependent boundary conditions, narrow passages and mixed boundary conditions at small windows. We present here two reduced modeling approaches for a fast computation of diffusing fluxes in microdomains. The first approach is based on a Markov mass-action law equations coupled to a Markov chain. The second is a Gillespie's method based on the narrow escape theory for coarse-graining the geometry of the domain into Poissonian rates. The main application concerns diffusion in cellular biology, where we compute as an example the distribution of arrival times of calcium ions to small hidden targets to trigger vesicular release.
Multiscale models and stochastic simulation methods for computing rare but key binding events in cell biology

International Nuclear Information System (INIS)

Guerrier, C.; Holcman, D.

2017-01-01

The main difficulty in simulating diffusion processes at a molecular level in cell microdomains is due to the multiple scales involving nano- to micrometers. Few to many particles have to be simulated and simultaneously tracked while there are exploring a large portion of the space for binding small targets, such as buffers or active sites. Bridging the small and large spatial scales is achieved by rare events representing Brownian particles finding small targets and characterized by long-time distribution. These rare events are the bottleneck of numerical simulations. A naive stochastic simulation requires running many Brownian particles together, which is computationally greedy and inefficient. Solving the associated partial differential equations is also difficult due to the time dependent boundary conditions, narrow passages and mixed boundary conditions at small windows. We present here two reduced modeling approaches for a fast computation of diffusing fluxes in microdomains. The first approach is based on a Markov mass-action law equations coupled to a Markov chain. The second is a Gillespie's method based on the narrow escape theory for coarse-graining the geometry of the domain into Poissonian rates. The main application concerns diffusion in cellular biology, where we compute as an example the distribution of arrival times of calcium ions to small hidden targets to trigger vesicular release.
Coping with adverse drug events in patients with heart failure : Exploring the role of medication beliefs and perceptions

NARCIS (Netherlands)

De Smedt, R. H.; Jaarsma, T.; Ranchor, A. V.; van der Meer, K.; Groenier, K. H.; Haaijer-Ruskamp, F. M.; Denig, P.

2012-01-01

This study describes coping strategies that patients with heart failure (HF) use to manage adverse drug events (ADEs). The included coping strategies were social support seeking, information seeking, non-adherence and taking alleviating medication. The role of beliefs about medication and ADE
Does short-term virologic failure translate to clinical events in antiretroviral-naïve patients initiating antiretroviral therapy in clinical practice?

DEFF Research Database (Denmark)

NN, NN; Mugavero, Michael J; May, Margaret

2008-01-01

, nevirapine, lopinavir/ritonavir, nelfinavir, or abacavir as third drugs in combination with a zidovudine and lamivudine nucleoside reverse transcriptase inhibitor backbone. MAIN OUTCOME MEASURES: Short-term (24-week) virologic failure (>500 copies/ml) and clinical events within 2 years of ART initiation.......58-2.22), lopinavir/ritonavir (1.32, 95% CI = 1.12-1.57), nelfinavir (3.20, 95% CI = 2.74-3.74), and abacavir (2.13, 95% CI = 1.82-2.50). However, the rate of clinical events within 2 years of ART initiation appeared higher only with nevirapine (adjusted hazard ratio for composite outcome measure 1.27, 95% CI = 1......OBJECTIVE: To determine whether differences in short-term virologic failure among commonly used antiretroviral therapy (ART) regimens translate to differences in clinical events in antiretroviral-naïve patients initiating ART. DESIGN: Observational cohort study of patients initiating ART between...
Of black swans and tossed coins: is the description-experience gap in risky choice limited to rare events?

Science.gov (United States)

Ludvig, Elliot A; Spetch, Marcia L

2011-01-01

When faced with risky decisions, people tend to be risk averse for gains and risk seeking for losses (the reflection effect). Studies examining this risk-sensitive decision making, however, typically ask people directly what they would do in hypothetical choice scenarios. A recent flurry of studies has shown that when these risky decisions include rare outcomes, people make different choices for explicitly described probabilities than for experienced probabilistic outcomes. Specifically, rare outcomes are overweighted when described and underweighted when experienced. In two experiments, we examined risk-sensitive decision making when the risky option had two equally probable (50%) outcomes. For experience-based decisions, there was a reversal of the reflection effect with greater risk seeking for gains than for losses, as compared to description-based decisions. This fundamental difference in experienced and described choices cannot be explained by the weighting of rare events and suggests a separate subjective utility curve for experience.
Of black swans and tossed coins: is the description-experience gap in risky choice limited to rare events?

Directory of Open Access Journals (Sweden)

Elliot A Ludvig

Full Text Available When faced with risky decisions, people tend to be risk averse for gains and risk seeking for losses (the reflection effect. Studies examining this risk-sensitive decision making, however, typically ask people directly what they would do in hypothetical choice scenarios. A recent flurry of studies has shown that when these risky decisions include rare outcomes, people make different choices for explicitly described probabilities than for experienced probabilistic outcomes. Specifically, rare outcomes are overweighted when described and underweighted when experienced. In two experiments, we examined risk-sensitive decision making when the risky option had two equally probable (50% outcomes. For experience-based decisions, there was a reversal of the reflection effect with greater risk seeking for gains than for losses, as compared to description-based decisions. This fundamental difference in experienced and described choices cannot be explained by the weighting of rare events and suggests a separate subjective utility curve for experience.
A study on the regulatory approach of KNGR multiple failure events

Energy Technology Data Exchange (ETDEWEB)

Chang, Keun Sun; Kweon, Y. C.; Kang, H. J.; Lee, S. J.; Cheong, D. Y.; Lee, Y. S.; Lee, M. K. [Sunmoon Univ., Asan (Korea, Republic of); Jeong, Ji Hwan [Baekseok College of Cultural studies, Cheonan (Korea, Republic of)

2001-01-15

This project is to provide the regulatory direction of containment bypass during multiple steam generator tube failure issue for the Korean Next Generation Reactors, which is a part of major technical issues resulted from the safety regulation R and D on the KNGR. The outstanding results are as follows : the Multiple Steam Generator Tube Repture(MSGTR) event has never been occurred in the history of commercial nuclear reactor operation but single Steam Generator Tube Rupture(SGTR) event is reported to occur every two years. A probabilistic safety analysis study on MSGTR event, however, show its probability of occurrence is to be the same order as the design basis accidents such as LACA. In this regard, the ability of NPPs to cope with MSGTR event is required. Some requirements on initial and boundary conditions are suggested to be used in the analyses of NPPs during MSGTR events. The items that should be considered in establishing regulatory requirements are summarized as follows : the analyses of MSGTR events should be performed by a best-estimate method with normal full power conditions except initial reactor power of 102%, all safety- and non-safety grade systems and components are assumed to be available only in automatic mode, tube ruptures are assumed to occur at the steam generator which is in the loop connected with a pressurizer, guillotine-type tube raptures are assumed near tube sheet on hot-leg side, the results of 1-5 tube ruptures should be compared, an appropriate break flow model should be used and critical flow model can be compared, an appropriate break flow model should be used and critical flow model can be used if needed, operator response time should be based on ANSI/ANS-51.1-1983 and ANSI/ANS-58.8-1984, acceptance criteria should be stated in terms of MSSV lift time as well as radiological consequences. It is recommended that some analyses should be carried out in order to figure out the effects of tube rupture modelling methods. A single
Top-down and bottom-up definitions of human failure events in human reliability analysis

International Nuclear Information System (INIS)

Boring, Ronald Laurids

2014-01-01

In the probabilistic risk assessments (PRAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approaches should arrive at the same set of HFEs. This question is crucial, however, as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PRAs tend to be top-down - defined as a subset of the PRA - whereas the HFEs used in petroleum quantitative risk assessments (QRAs) often tend to be bottom-up - derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications.
Apixaban: Effective and Safe in Preventing Thromboembolic Events in Patients with Atrial Fibrillation and Renal Failure.

Science.gov (United States)

Cortese, Francesca; Scicchitano, Pietro; Gesualdo, Michele; Ricci, Gabriella; Carbonara, Santa; Franchini, Carlo; Pia Schiavone, Brigida Immacolata; Corbo, Filomena; Ciccone, Marco Matteo

2017-11-17

Thromboembolic events, principally stroke, represent one of the leading causes of morbidity and mortality among subjects with atrial fibrillation. Chronic kidney disease determines a further increase of thromboembolic events, bleeding and mortality and complicates the pharmacological management of patients with atrial fibrillation, mainly due to the side effects of antiarrhythmic and anticoagulant drugs with renal excretion. Apixaban is a new oral anticoagulant characterized by good bioavailability and renal elimination accounting for only 25%, showing a safety profile and effectiveness in patients with renal impairment. In this manuscript, we reviewed literature data on the use of apixaban in the management of non-valvular atrial fibrillation in patients with renal failure, in order to clarify an often-debated topic in clinical practice. A PubMed search was performed on the terms atrial fibrillation, apixaban and renal failure with the aim of identifying relevant manuscripts, large randomized clinical trials, meta-analyses, and current guidelines. Literature data show that apixaban could represent an interesting alternative to warfarin and other selective antagonists of coagulation factors in patients with impaired renal function. About the risk of major bleeding, apixaban appears to be safer than warfarin in the presence of any degree of renal failure. Apixaban show to be an effective anticoagulant in patients with atrial fibrillation, even superior to warfarin in reducing the risk of stroke and systemic embolism regardless of the presence of renal insufficiency. Moreover, Food and Drug Administration allows the use of apixaban in patients with end stage renal disease on hemodialysis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
Maxillary hyperplasia and hyperostosis cranialis: a rare manifestation of renal osteodystrohy in a patient with hyperparathyroidism secondary to chronic renal failure

International Nuclear Information System (INIS)

Bakathir, Abdulaziz A.; Margasahayam, Manjunath V.; Al-Ismaily, Mohammad I.

2008-01-01

This case report describes a 21-year-old female patient with a complex medical condition of end-stage chronic renal failure and secondary hyperparathyroidism presenting with a history of gradual enlargement of facial bones over a period of one year. The facial enlargement primarily involves the maxilla causing a bizarre facial and dental deformity. Based on the clinical, radiographic and laboratory investigations the facial deformity was confirmed as a rare manifestation of renal osteodystrophy presenting as maxillary hyperplasia and hyperostosis cranialis. (author)
Accuracy-Energy Configurable Sensor Processor and IoT Device for Long-Term Activity Monitoring in Rare-Event Sensing Applications

Directory of Open Access Journals (Sweden)

Daejin Park

2014-01-01

Full Text Available A specially designed sensor processor used as a main processor in IoT (internet-of-thing device for the rare-event sensing applications is proposed. The IoT device including the proposed sensor processor performs the event-driven sensor data processing based on an accuracy-energy configurable event-quantization in architectural level. The received sensor signal is converted into a sequence of atomic events, which is extracted by the signal-to-atomic-event generator (AEG. Using an event signal processing unit (EPU as an accelerator, the extracted atomic events are analyzed to build the final event. Instead of the sampled raw data transmission via internet, the proposed method delays the communication with a host system until a semantic pattern of the signal is identified as a final event. The proposed processor is implemented on a single chip, which is tightly coupled in bus connection level with a microcontroller using a 0.18 μm CMOS embedded-flash process. For experimental results, we evaluated the proposed sensor processor by using an IR- (infrared radio- based signal reflection and sensor signal acquisition system. We successfully demonstrated that the expected power consumption is in the range of 20% to 50% compared to the result of the basement in case of allowing 10% accuracy error.
Heart Failure

OpenAIRE

McMurray, John; Ponikowski, Piotr

2011-01-01

Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure.
CRITICAL EVENTS IN CONSTRUCTION PROCESS

DEFF Research Database (Denmark)

Jørgensen, Kirsten; Rasmussen, Grane Mikael Gregaard

2009-01-01

cause-effects of failures and defects in the construction industry by using an analytical approach (The bowtie model) which is developed in the accident research. Using this model clarifies the relationships within the chain of failures that causes critical events with undesirable consequences......Function failures, defects and poor communication are major problems in the construction industry. These failures and defects are caused by a row of critical events in the construction process. The purpose of this paper is to define “critical events” in the construction process and to investigate....... In this way the causes of failures and the relationships between various failures are rendered visible. A large construction site was observed from start to finish as the empirical element in the research. The research focuses on all kinds of critical events identified throughout every phase during...
Non-selective vs. selective beta-blocker treatment and the risk of thrombo-embolic events in patients with heart failure

NARCIS (Netherlands)

de Peuter, Olav R.; Souverein, Patrick C.; Klungel, Olaf H.; Büller, Harry R.; de Boer, Anthonius; Kamphuisen, Pieter W.

2011-01-01

Aims Heart failure (HF) is associated with a prothrombotic state, resulting in an increased risk for thrombo-embolic events. Studies suggest a reduced prothrombotic state when non-selective beta-blockers relative to selective beta-blockers are given. We studied the influence of non-selective

Probabilistic analysis of ''common mode failures''

International Nuclear Information System (INIS)

Easterling, R.G.

1978-01-01

Common mode failure is a topic of considerable interest in reliability and safety analyses of nuclear reactors. Common mode failures are often discussed in terms of examples: two systems fail simultaneously due to an external event such as an earthquake; two components in redundant channels fail because of a common manufacturing defect; two systems fail because a component common to both fails; the failure of one system increases the stress on other systems and they fail. The common thread running through these is a dependence of some sort--statistical or physical--among multiple failure events. However, the nature of the dependence is not the same in all these examples. An attempt is made to model situations, such as the above examples, which have been termed ''common mode failures.'' In doing so, it is found that standard probability concepts and terms, such as statistically dependent and independent events, and conditional and unconditional probabilities, suffice. Thus, it is proposed that the term ''common mode failures'' be dropped, at least from technical discussions of these problems. A corollary is that the complementary term, ''random failures,'' should also be dropped. The mathematical model presented may not cover all situations which have been termed ''common mode failures,'' but provides insight into the difficulty of obtaining estimates of the probabilities of these events
BACFIRE, Minimal Cut Sets Common Cause Failure Fault Tree Analysis

International Nuclear Information System (INIS)

Fussell, J.B.

1983-01-01

1 - Description of problem or function: BACFIRE, designed to aid in common cause failure analysis, searches among the basic events of a minimal cut set of the system logic model for common potential causes of failure. The potential cause of failure is called a qualitative failure characteristics. The algorithm searches qualitative failure characteristics (that are part of the program input) of the basic events contained in a set to find those characteristics common to all basic events. This search is repeated for all cut sets input to the program. Common cause failure analysis is thereby performed without inclusion of secondary failure in the system logic model. By using BACFIRE, a common cause failure analysis can be added to an existing system safety and reliability analysis. 2 - Method of solution: BACFIRE searches the qualitative failure characteristics of the basic events contained in the fault tree minimal cut set to find those characteristics common to all basic events by either of two criteria. The first criterion can be met if all the basic events in a minimal cut set are associated by a condition which alone may increase the probability of multiple component malfunction. The second criterion is met if all the basic events in a minimal cut set are susceptible to the same secondary failure cause and are located in the same domain for that cause of secondary failure. 3 - Restrictions on the complexity of the problem - Maxima of: 1001 secondary failure maps, 101 basic events, 10 cut sets
Unbiased multi-fidelity estimate of failure probability of a free plane jet

Science.gov (United States)

Marques, Alexandre; Kramer, Boris; Willcox, Karen; Peherstorfer, Benjamin

2017-11-01

Estimating failure probability related to fluid flows is a challenge because it requires a large number of evaluations of expensive models. We address this challenge by leveraging multiple low fidelity models of the flow dynamics to create an optimal unbiased estimator. In particular, we investigate the effects of uncertain inlet conditions in the width of a free plane jet. We classify a condition as failure when the corresponding jet width is below a small threshold, such that failure is a rare event (failure probability is smaller than 0.001). We estimate failure probability by combining the frameworks of multi-fidelity importance sampling and optimal fusion of estimators. Multi-fidelity importance sampling uses a low fidelity model to explore the parameter space and create a biasing distribution. An unbiased estimate is then computed with a relatively small number of evaluations of the high fidelity model. In the presence of multiple low fidelity models, this framework offers multiple competing estimators. Optimal fusion combines all competing estimators into a single estimator with minimal variance. We show that this combined framework can significantly reduce the cost of estimating failure probabilities, and thus can have a large impact in fluid flow applications. This work was funded by DARPA.
On the importance of analyzing flood defense failures

Directory of Open Access Journals (Sweden)

Özer Işıl Ece

2016-01-01

Full Text Available Flood defense failures are rare events but when they do occur lead to significant amounts of damage. The defenses are usually designed for rather low-frequency hydraulic loading and as such typically at least high enough to prevent overflow. When they fail, flood defenses like levees built with modern design codes usually either fail due to wave overtopping or geotechnical failure mechanisms such as instability or internal erosion. Subsequently geotechnical failures could trigger an overflow leading for the breach to grow in size Not only the conditions relevant for these failure mechanisms are highly uncertain, also the model uncertainty in geomechanical, internal erosion models, or breach models are high compared to other structural models. Hence, there is a need for better validation and calibration of models or, in other words, better insight in model uncertainty. As scale effects typically play an important role and full-scale testing is challenging and costly, historic flood defense failures can be used to provide insights into the real failure processes and conditions. The recently initiated SAFElevee project at Delft University of Technology aims to exploit this source of information by performing back analysis of levee failures at different level of detail. Besides detailed process based analyses, the project aims to investigate spatial and temporal patterns in deformation as a function of the hydrodynamic loading using satellite radar interferometry (i.e. PS-InSAR in order to examine its relation with levee failure mechanisms. The project aims to combine probabilistic approaches with the mechanics of the various relevant failure mechanisms to reduce model uncertainty and propose improvements to assessment and design models. This paper describes the approach of the study to levee breach analysis and the use of satellites for breach initiation analysis, both adopted within the SAFElevee project.
Immune mediated liver failure

OpenAIRE

Wang, Xiaojing; Ning, Qin

2014-01-01

Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capac...
Nonacetaminophen Drug-Induced Acute Liver Failure.

Science.gov (United States)

Thomas, Arul M; Lewis, James H

2018-05-01

Acute liver failure of all causes is diagnosed in between 2000 and 2500 patients annually in the United States. Drug-induced acute liver failure is the leading cause of acute liver failure, accounting for more than 50% of cases. Nonacetaminophen drug injury represents 11% of all cases in the latest registry from the US Acute Liver Failure Study Group. Although rare, acute liver failure is clinically dramatic when it occurs, and requires a multidisciplinary approach to management. In contrast with acetaminophen-induced acute liver failure, non-acetaminophen-induced acute liver failure has a more ominous prognosis with a lower liver transplant-free survival. Copyright © 2018 Elsevier Inc. All rights reserved.
Rare post-operative complications of large mediastinal tumor resection

Directory of Open Access Journals (Sweden)

Mohsen Mirmohammadsadeghi

2015-03-01

Full Text Available Background: There are some reports in the literature, which suggest that cardiac tamponade drainage may transiently affect systolic function and also cause acute respiratory distress syndrome (ARDS. We did not find any reports of acute ventricular failure and ARDS secondary to mediastinal tumor resection without tamponade. Case Report: Here we report a 48-year-old woman presenting with massive pericardial effusion without tamponade in whom tumor was resected through median sternotomy using cardiopulmonary bypass. ARDS and acute heart failure were two rare complications that happened at the end of the operation secondary to a sudden decompression of the heart from tumor pressure. Conclusion: ARDS and acute heart failure are two rare complications, which can happen after large mediastinal tumor resection.
Multimodality Renal Failure in a Patient with OEIS Complex

Directory of Open Access Journals (Sweden)

Jonathan D. Santoro

2015-10-01

Full Text Available Omphalocele-exstrophy of the bladder-imperforate anus-spinal defect (OEIS complex is a rare constellation of clinical abnormalities with wide phenotypic presentation. We describe a case of a preterm neonate with OEIS complex with acute renal failure, and the challenges in diagnosis and management of this patient as renal failure can be a multifactorial process when encountered with this rare complex.
Infantile Renovascular Hypertension with Failure to Thrive.

Science.gov (United States)

Phillips, Amanda R; Eliason, Jonathan L; Stanley, James C; Coleman, Dawn M

2016-05-01

Severe hypertension in infancy is a rare cause of failure to thrive. The successful surgical management of this disease in an infant having refractory renovascular hypertension and growth failure is reported. Copyright © 2016 Elsevier Inc. All rights reserved.
One Size Does Not Fit All: Human Failure Event Decomposition and Task Analysis

Energy Technology Data Exchange (ETDEWEB)

Ronald Laurids Boring, PhD

2014-09-01

In the probabilistic safety assessments (PSAs) used in the nuclear industry, human failure events (HFEs) are determined as a subset of hardware failures, namely those hardware failures that could be triggered or exacerbated by human action or inaction. This approach is top-down, starting with hardware faults and deducing human contributions to those faults. Elsewhere, more traditionally human factors driven approaches would tend to look at opportunities for human errors first in a task analysis and then identify which of those errors is risk significant. The intersection of top-down and bottom-up approaches to defining HFEs has not been carefully studied. Ideally, both approaches should arrive at the same set of HFEs. This question remains central as human reliability analysis (HRA) methods are generalized to new domains like oil and gas. The HFEs used in nuclear PSAs tend to be top-down—defined as a subset of the PSA—whereas the HFEs used in petroleum quantitative risk assessments (QRAs) are more likely to be bottom-up—derived from a task analysis conducted by human factors experts. The marriage of these approaches is necessary in order to ensure that HRA methods developed for top-down HFEs are also sufficient for bottom-up applications. In this paper, I first review top-down and bottom-up approaches for defining HFEs and then present a seven-step guideline to ensure a task analysis completed as part of human error identification decomposes to a level suitable for use as HFEs. This guideline illustrates an effective way to bridge the bottom-up approach with top-down requirements.
Fascinating world of rare earth research

International Nuclear Information System (INIS)

Gschneidner, K.A. Jr.

1977-01-01

The first part of this paper concerns some of the notable events which occurred early in the author's career as a rare earther and some of the major events which took place in the two decades 1950 to 1970. The notable changes and advances in the rare earth research world since the 1971 Durham Conference are described in the second and largest part of the paper. The final portion is concerned with actinide developments since 1971
Oxaliplatin-Induced Leukocytoclastic Vasculitis under Adjuvant Chemotherapy for Colorectal Cancer: Two Cases of a Rare Adverse Event

Directory of Open Access Journals (Sweden)

Henriette Quack

2013-12-01

Full Text Available Leukocytoclastic vasculitis is a multicausal systemic inflammatory disease of the small vessels, histologically characterized by inflammation and deposition of both nuclear debris and fibrin in dermal postcapillary venules. The clinical picture typically involves palpable purpura of the lower legs and may be associated with general symptoms such as fatigue, arthralgia and fever. Involvement of the internal organs, most notably the kidneys, the central nervous system or the eyes, is possible and determines the prognosis. Oxaliplatin-induced leukocytoclastic vasculitis is a very rare event that limits treatment options in affected patients. We report 2 patients who developed the condition under chemotherapy for advanced rectal and metastatic colon carcinoma, respectively; a termination of the therapy was therefore necessary. While current therapies for colorectal cancer include the combination of multimodal treatment with new and targeted agents, rare and unusual side effects elicited by established agents also need to be taken into account for the clinical management.
Local sequence alignments statistics: deviations from Gumbel statistics in the rare-event tail

Directory of Open Access Journals (Sweden)

Burghardt Bernd

2007-07-01

Full Text Available Abstract Background The optimal score for ungapped local alignments of infinitely long random sequences is known to follow a Gumbel extreme value distribution. Less is known about the important case, where gaps are allowed. For this case, the distribution is only known empirically in the high-probability region, which is biologically less relevant. Results We provide a method to obtain numerically the biologically relevant rare-event tail of the distribution. The method, which has been outlined in an earlier work, is based on generating the sequences with a parametrized probability distribution, which is biased with respect to the original biological one, in the framework of Metropolis Coupled Markov Chain Monte Carlo. Here, we first present the approach in detail and evaluate the convergence of the algorithm by considering a simple test case. In the earlier work, the method was just applied to one single example case. Therefore, we consider here a large set of parameters: We study the distributions for protein alignment with different substitution matrices (BLOSUM62 and PAM250 and affine gap costs with different parameter values. In the logarithmic phase (large gap costs it was previously assumed that the Gumbel form still holds, hence the Gumbel distribution is usually used when evaluating p-values in databases. Here we show that for all cases, provided that the sequences are not too long (L > 400, a "modified" Gumbel distribution, i.e. a Gumbel distribution with an additional Gaussian factor is suitable to describe the data. We also provide a "scaling analysis" of the parameters used in the modified Gumbel distribution. Furthermore, via a comparison with BLAST parameters, we show that significance estimations change considerably when using the true distributions as presented here. Finally, we study also the distribution of the sum statistics of the k best alignments. Conclusion Our results show that the statistics of gapped and ungapped local
Acute liver failure

DEFF Research Database (Denmark)

Bernal, William; Lee, William M; Wendon, Julia

2015-01-01

Over the last three decades acute liver failure (ALF) has been transformed from a rare and poorly understood condition with a near universally fatal outcome, to one with a well characterized phenotype and disease course. Complex critical care protocols are now applied and emergency liver...
Spatial and temporal patterns of bank failure during extreme flood events: Evidence of nonlinearity and self-organised criticality at the basin scale?

Science.gov (United States)

Thompson, C. J.; Croke, J. C.; Grove, J. R.

2012-04-01

Non-linearity in physical systems provides a conceptual framework to explain complex patterns and form that are derived from complex internal dynamics rather than external forcings, and can be used to inform modeling and improve landscape management. One process that has been investigated previously to explore the existence of self-organised critical system (SOC) in river systems at the basin-scale is bank failure. Spatial trends in bank failure have been previously quantified to determine if the distribution of bank failures at the basin scale exhibit the necessary power law magnitude/frequency distributions. More commonly bank failures are investigated at a small-scale using several cross-sections with strong emphasis on local-scale factors such as bank height, cohesion and hydraulic properties. Advancing our understanding of non-linearity in such processes, however, requires many more studies where both the spatial and temporal measurements of the process can be used to investigate the existence or otherwise of non-linearity and self-organised criticality. This study presents measurements of bank failure throughout the Lockyer catchment in southeast Queensland, Australia, which experienced an extreme flood event in January 2011 resulting in the loss of human lives and geomorphic channel change. The most dominant form of fluvial adjustment consisted of changes in channel geometry and notably widespread bank failures, which were readily identifiable as 'scalloped' shaped failure scarps. The spatial extents of these were mapped using high-resolution LiDAR derived digital elevation model and were verified by field surveys and air photos. Pre-flood event LiDAR coverage for the catchment also existed allowing direct comparison of the magnitude and frequency of bank failures from both pre and post-flood time periods. Data were collected and analysed within a GIS framework and investigated for power-law relationships. Bank failures appeared random and occurred
Effect of enhanced external counterpulsation therapy on myeloperoxidase in lowering cardiovascular events of patients with chronic heart failure

Directory of Open Access Journals (Sweden)

Starry H. Rampengan

2013-08-01

Full Text Available Background: Chronic heart failure (CHF is a slowly progressive disease with high morbidity and mortality; therefore, the management using pharmacological treatments frequently fails to improve outcome. Enhanced external counterpulsation (EECP, a non-invasive treatment, may serve as alternative treatment for heart failure. This study was aimed to evaluate the influence of EECP on myeloperoxidase (MPO as inflammatory marker as well as cardiac events outcome.Methods: This was an open randomized controlled clinical trial on 66 CHF patients visiting several cardiovascular clinics in Manado between January-December 2012. The subjects were randomly divided into two groups, i.e. the group who receive EECP therapy and those who did not receive EECP therapy with 33 patients in each group. Myeloperoxidase (MPO as inflammatory marker was examined at baseline and after 6 months of observation. Cardiovascular events were observed as well after 6 months of observation. Unpaired t-test was use to analyze the difference of MPO between the two groups, and chi-square followed by calculation of relative risk were used for estimation of cardiovascular event outcomes.Results: MPO measurement at baseline and after 6 months in EECP group were 643.16 ± 239.40 pM and 422.31 ± 156.26 pM, respectively (p < 0.001. Whereas in non EECP group, the MPO values were 584.69 ± 281.40 pM and 517.64 ± 189.68 pM, repectively (p = 0.792. MPO reduction was observed in all patients of EECP group and in 13 patients (48% of non-EECP group (p < 0.001. Cardiovascular events were observed in 7 (21.21% and 15 (45.45% of patients in EECP and non-EECP groups, respectively (p = 0.037.Conclusion: EECP therapy significantly decreased the level of MPO as inflammatory marker and this decrease was correlated with the reduction of cardiovascular events in CHF patients. (Med J Indones. 2013;22:152-60. doi: 10.13181/mji.v22i3.584Keywords: CHF, cardiovascular events, EECP, myeloperoxidase
Oncogenic events associated with endometrial and ovarian cancers are rare in endometriosis

DEFF Research Database (Denmark)

Vestergaard, Anna Lindeløv; Thorup, Katrine; Knudsen, Ulla Breth

2011-01-01

Endometriosis displays some features that resemble malignant processes, including invasive growth, resistance to apoptosis, and distant implantation. The objective of this study was to investigate whether gene alterations that are frequent in endometrial and/or ovarian cancers contribute to the p......Endometriosis displays some features that resemble malignant processes, including invasive growth, resistance to apoptosis, and distant implantation. The objective of this study was to investigate whether gene alterations that are frequent in endometrial and/or ovarian cancers contribute...... to the pathogenesis of endometriosis. Biopsies were obtained from ectopic endometriosis lesions from 23 patients with revised American Fertility Score (rAFS) stage 1 (N=1), 2 (N=10), 3 (N=11), or 4 (N=1) endometriosis. Six genes (APC, CDKN2A, PYCARD, RARB, RASSF1, and ESR1) were analyzed for promoter hypermethylation...... in a single lesion. No gene alterations were found in the remaining samples. Our data suggest that genetic and epigenetic events contributing to endometrial and ovarian cancers are rare in endometriosis. However, other proto-oncogenes and tumor suppressor genes should be tested for alterations in order...
[Clinical case of acute renal failure revealing an autoimmune hypothyroidism].

Science.gov (United States)

Montasser, Dina Ibrahim; Hassani, Mohamed; Zajjari, Yassir; Bahadi, Abdelali; Alayoud, Ahmed; Hamzi, Amine; Hassani, Kawtar; Moujoud, Omar; Asseraji, Mohamed; Kadiri, Moncif; Aatif, Taoufik; El Kabbaj, Driss; Benyahia, Mohamed; Allam, Mustapha; Akhmouch, Ismail; Oualim, Zouhir

2010-04-01

Although the clinic picture is often indicative of muscle manifestations in patients with hypothyroidism, signs and symptoms of this condition are variable from simple elevation of serum muscle enzymes with myalgia, muscle weakness, cramps to rhabdomyolysis with acute renal failure which remains a rare event. Thyroid hormones affect the function of almost every body organ, and thyroid dysfunction produces a wide range of metabolic disturbances. Hypothyroidism is associated with significant effects on the kidney which the pathophysiology seems to be multifactorial, but the exact mechanisms remain poorly understood. Hypothyroidism as a cause of renal impairment is usually overlooked, leading to unnecessary diagnostic procedures. The main objective of our observation is to report a case of acute renal failure revealing an autoimmune hypothyroidism in which thyroid hormone substitution led to a significant improvement in muscular, thyroid and renal disorders. Copyright 2010 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.
A Case Against Fancy Decorated Drinks: Multi-Organ Failure After Drinking a Mojito Cocktail

Directory of Open Access Journals (Sweden)

Simon Bac

2016-09-01

Full Text Available We present the first case of gastro-intestinal perforation caused by a mint twig decorating a cocktail drink. A 76-year-old man was enjoying his Mojito cocktail on a cruise ship near Mexico when he accidently swallowed a mint twig, resulting in ileum perforation. This led to a cascade of events, eventually resulting in life-threatening multi-organ failure. Given this rare but potentially severe complication and the increasing popularity of decorated drinks, a less ‘fancy’ presentation for cocktails and similar drinks may be warranted.
ICDE project report: collection and analysis of common-cause failures of motor operated valves

International Nuclear Information System (INIS)

2001-07-01

This report documents a study performed on the set of common cause failures (CCF) of motor operated valves (MOV). The data studied here were derived from the International CCF Data Exchange (ICDE) database, to which several countries have submitted CCF event data. The purpose of the ICDE is to allow multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses that include CCF modeling. Because CCF events are typically rare events, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, yields sufficient data for more rigorous analyses. This report is the result of an in-depth review of the MOV events and presents several insights about them. The objective of this document is to look beyond the CCF parameter estimates that can be obtained from the CCF data, to gain further understanding of why CCF events occur and what measures may be taken to prevent, or at least mitigate the effect of MOV CCF events. The report presents details of the ICDE project, a quantitative presentation of the MOV events, and a discussion of some engineering aspects of the events. (authors)

Does short-term virologic failure translate to clinical events in antiretroviral-naïve patients initiating antiretroviral therapy in clinical practice?

NARCIS (Netherlands)

Mugavero, Michael J; May, Margaret; Harris, Ross; Saag, Michael S; Costagliola, Dominique; Egger, Matthias; Phillips, Andrew; Günthard, Huldrych F; Dabis, Francois; Hogg, Robert; de Wolf, Frank; Fatkenheuer, Gerd; Gill, M John; Justice, Amy; D'Arminio Monforte, Antonella; Lampe, Fiona; Miró, Jose M; Staszewski, Schlomo; Sterne, Jonathan A C; Niesters, Bert

2008-01-01

OBJECTIVE: To determine whether differences in short-term virologic failure among commonly used antiretroviral therapy (ART) regimens translate to differences in clinical events in antiretroviral-naïve patients initiating ART. DESIGN: Observational cohort study of patients initiating ART between
Potential for fuel melting and cladding thermal failure during a PCM event in LWRs

International Nuclear Information System (INIS)

El-Genk, M.S.; Croucher, D.W.

1979-01-01

The primary concern in nuclear reactor safety is to ensure that no conceivable accident, whether initiated by a failure of the reactor system or by incorrect operation, will lead to a dangerous release of radiation to the environment. A number of hypothesized off-normal power or cooling conditions, generally termed as power-cooling-mismatch (PCM) accidents, are considered in the safety analysis of light water reactors (LWRs). During a PCM accident, film boiling may occur at the cladding surface and cause a rapid temperature increase in the fuel and the cladding, perhaps producing embrittlement of the zircaloy cladding by oxidation. Molten fuel may be produced at the center of the pellets, extrude radially through open cracks in the outer, unmelted portion of the pellet and relocate in the fuel-cladding gap. If the amount of extruded molten fuel is sufficient to establish contact with the cladding, which is at a high temperature during film boiling, the zircaloy cladding may melt. The present work assesses the potential for central fuel melting and thermal failure of the zircaloy cladding due to melting upon being contacted by extruded molten UO 2 -fuel during a PCM event
A Hybrid Monte Carlo importance sampling of rare events in Turbulence and in Turbulent Models

Science.gov (United States)

Margazoglou, Georgios; Biferale, Luca; Grauer, Rainer; Jansen, Karl; Mesterhazy, David; Rosenow, Tillmann; Tripiccione, Raffaele

2017-11-01

Extreme and rare events is a challenging topic in the field of turbulence. Trying to investigate those instances through the use of traditional numerical tools turns to be a notorious task, as they fail to systematically sample the fluctuations around them. On the other hand, we propose that an importance sampling Monte Carlo method can selectively highlight extreme events in remote areas of the phase space and induce their occurrence. We present a brand new computational approach, based on the path integral formulation of stochastic dynamics, and employ an accelerated Hybrid Monte Carlo (HMC) algorithm for this purpose. Through the paradigm of stochastic one-dimensional Burgers' equation, subjected to a random noise that is white-in-time and power-law correlated in Fourier space, we will prove our concept and benchmark our results with standard CFD methods. Furthermore, we will present our first results of constrained sampling around saddle-point instanton configurations (optimal fluctuations). The research leading to these results has received funding from the EU Horizon 2020 research and innovation programme under Grant Agreement No. 642069, and from the EU Seventh Framework Programme (FP7/2007-2013) under ERC Grant Agreement No. 339032.
Failure of hippocampal deactivation during loss events in treatment-resistant depression.

Science.gov (United States)

Johnston, Blair A; Tolomeo, Serenella; Gradin, Victoria; Christmas, David; Matthews, Keith; Steele, J Douglas

2015-09-01

Major depressive disorder is characterized by anhedonia, cognitive biases, ruminations, hopelessness and increased anxiety. Blunted responses to rewards have been reported in a number of recent neuroimaging and behavioural studies of major depressive disorder. In contrast, neural responses to aversive events remain an under-studied area. While selective serotonergic reuptake inhibitors are often effective in treating major depressive disorder, their mechanism of action remains unclear. Following a series of animal model investigations of depressive illness and serotonergic function, Deakin and Graeff predicted that brain activity in patients with major depressive disorder is associated with an overactive dorsal raphe nucleus with overactive projections to the amygdala, periaqueductal grey and striatum, and an underactive median raphe nucleus with underactive projections to the hippocampus. Here we describe an instrumental loss-avoidance and win-gain reinforcement learning functional magnetic resonance imaging study with 40 patients with highly treatment-resistant major depressive disorder and never-depressed controls. The dorsal raphe nucleus/ periaqueductal grey region of the midbrain and hippocampus were found to be overactive in major depressive disorder during unsuccessful loss-avoidance although the median raphe nucleus was not found to be underactive. Hippocampal overactivity was due to a failure to deactivate during loss events in comparison to controls, and hippocampal over-activity correlated with depression severity, self-report 'hopelessness' and anxiety. Deakin and Graeff argued that the median raphe nucleus normally acts to inhibit consolidation of aversive memories via the hippocampus and this system is underactive in major depressive disorder, facilitating the development of ruminations, while the dorsal raphe nucleus system is engaged by distal cues predictive of threats and is overactive in major depressive disorder. During win events the striatum
Estimation of common cause failure parameters for diesel generators

International Nuclear Information System (INIS)

Tirira, J.; Lanore, J.M.

2002-10-01

This paper presents a summary of some results concerning the feedback analysis of French Emergency diesel generator (EDG). The database of common cause failure for EDG has been updated. The data collected covers a period of 10 years. Several latent common cause failure (CCF) events counting in tens are identified. In fact, in this number of events collected, most are potential CCF. From events identified, 15% events are characterized as complete CCF. The database is organised following the structure proposed by 'International Common Cause Data Exchange' (ICDE project). Events collected are analyzed by failure mode and degree of failure. Qualitative analysis of root causes, coupling factors and corrective actions are studied. The exercise of quantitative analysis is in progress for evaluating CCF parameters taking into account the average impact vector and the rate of the independent failures. The interest of the average impact vector approach is that it makes it possible to take into account a wide experience feedback, not limited to complete CCF but including also many events related to partial or potential CCF. It has to be noted that there are no finalized quantitative conclusions yet to be drawn and analysis is in progress for evaluating diesel CCF parameters. In fact, the numerical coding CCF representation of the events uses a part of subjective analysis, which requests a complete and detailed event examination. (authors)
Amyotrophic Lateral Sclerosis Presenting Respiratory Failure as the Sole Initial Manifestation

Directory of Open Access Journals (Sweden)

Fuyuki Tateno

2014-08-01

Full Text Available It is rare that amyotrophic lateral sclerosis (ALS presents with respiratory failure as the sole initial manifestation. A 72-year-old man with mild chronic obstructive pulmonary disease developed exertional dyspnea for 13 months. He then progressed to limb weakness that led to the diagnosis of ALS. Although rare, ALS can present with respiratory failure as the sole initial manifestation more than 1 year prior to limb weakness.
Acute tubulo-interstitial nephritis leading to acute renal failure following multiple hornet stings

Directory of Open Access Journals (Sweden)

Bambery Pradeep

2006-11-01

Full Text Available Abstract Background Hornet stings are generally associated with local and occasionally anaphylactic reactions. Rarely systemic complications like acute renal failure can occur following multiple stings. Renal failure is usually due to development of acute tubular necrosis as a result of intravascular haemolysis, rhabdomyolysis or shock. Rarely it can be following development of acute tubulo-interstitial nephritis. Case presentation We describe a young male, who was stung on face, head, shoulders and upper limbs by multiple hornets (Vespa orientalis. He developed acute renal failure as a result of acute tubulo-interstitial nephritis and responded to steroids. Conclusion Rare causes of acute renal failure like tubulo-interstitial nephritis should be considered in a patient with persistent oliguria and azotemia following multiple hornet stings. Renal biopsy should be undertaken early, as institution of steroid therapy may help in recovery of renal function
Dependent failures of diesel generators

International Nuclear Information System (INIS)

Mankamo, T.; Pulkkinen, U.

1982-01-01

This survey of dependent failures (common-cause failures) is based on the data of diesel generator failures in U. S. nuclear power plants as reported in Licensee Event Reports. Failures were classified into random and potentially dependent failures. All failures due to design errors, manufacturing or installation errors, maintenance errors, or deviations in the operational environment were classified as potentially dependent failures.The statistical dependence between failures was estimated from the relative portion of multiple failures. Results confirm the earlier view of the significance of statistical dependence, a strong dependence on the age of the diesel generator was found in each failure class excluding random failures and maintenance errors, which had a nearly constant frequency independent of diesel generator age
ISS Ammonia Pump Failure, Recovery, and Lesson Learned A Hydrodynamic Bearing Perspective

Science.gov (United States)

Bruckner, Robert J.; Manco, Richard A., II

2014-01-01

The design, development, and operation of long duration spaceflight hardware has become an evolutionary process in which meticulous attention to details and lessons learned from previous experiences play a critical role. Invaluable to this process is the ability to retrieve and examine spaceflight hardware that has experienced a premature failure. While these situations are rare and unfortunate, the failure investigation and recovery from the event serve a valuable purpose in advancing future space mechanism development. Such a scenario began on July 31, 2010 with the premature failure of an ammonia pump on the external active thermal control system of the International Space Station. The ground-based inspections of the returned pump and ensuing failure investigation revealed five potential bearing forces that were un-accounted for in the design phase and qualification testing of the pump. These forces could combine in a number of random orientations to overload the pump bearings leading to solid-surface contact, wear, and premature failure. The recovery plan identified one of these five forces as being related to the square of the operating speed of the pump and this fact was used to recover design life through a change in flight rules for the operation of the pump module. Through the course of the failure investigation, recovery, and follow-on assessment of pump wear life, design guidance has been developed to improve the life of future mechanically pumped thermal control systems for both human and robotic exploration missions.
Acute Cardiac Failure in a Pregnant Woman due to Thyrotoxic Crisis

Directory of Open Access Journals (Sweden)

Nao Okuda

2012-01-01

Full Text Available Introduction. Cardiac failure during pregnancy is usually related to preeclampsia/eclampsia, rarely to hyperthyroidism. While hyperthyroidism can easily lead to hypertensive cardiac failure and may harm the fetus, it is sometimes difficult to distinguish hyperthyroidism from normal pregnancy. Case Presentation. We encountered a case of 41-year-old pregnant woman with hypertensive cardiac failure. Because we initially diagnosed as pre-eclampsia/eclampsia, Caesarian section was performed. However, her symptoms still persisted after delivery. After thyroid function test results taken on the day of admission were obtained on the fourth day, we could diagnose that her cardiac failure was caused by thyrotoxic crisis. Conclusions. Hypertensive cardiac failure due to hyperthyroidism during pregnancy is rare and difficult to diagnose because of similar presentation of normal pregnancy. However, physicians should be aware of the risks posed by hyperthyroidism during pregnancy.
Diffuse corpus callosum infarction - Rare vascular entity with differing etiology.

Science.gov (United States)

Mahale, Rohan; Mehta, Anish; Buddaraju, Kiran; John, Aju Abraham; Javali, Mahendra; Srinivasa, Rangasetty

2016-01-15

Infarctions of the corpus callosum are rare vascular events. It is relatively immune to vascular insult because of its rich vascular supply from anterior and posterior circulations of brain. Report of 3 patients with largely diffuse acute corpus callosum infarction. 3 patients with largely diffuse acute corpus callosum infarction were studied and each of these 3 patients had 3 different aetiologies. The 3 different aetiologies of largely diffuse acute corpus callosum infarction were cardioembolism, tuberculous arteritis and takayasu arteritis. Diffuse corpus callosum infarcts are rare events. This case series narrates the three different aetiologies of diffuse acute corpus callosum infarction which is a rare vascular event. Copyright © 2015 Elsevier B.V. All rights reserved.
Higher dietary lycopene intake is associated with longer cardiac event-free survival in patients with heart failure.

Science.gov (United States)

Biddle, Martha; Moser, Debra; Song, Eun Kyeung; Heo, Seongkum; Payne-Emerson, Heather; Dunbar, Sandra B; Pressler, Susan; Lennie, Terry

2013-08-01

The antioxidant lycopene may be beneficial for patients with heart failure (HF). Processed tomato products are a major source of lycopene, although they are also high in sodium. Increased sodium intake may counter the positive antioxidant effect of lycopene. This was a prospective study of 212 patients with HF. Dietary intake of lycopene and sodium was obtained from weighted 4-day food diaries. Patients were grouped by the median split of lycopene of 2471 µg/day and stratified by daily sodium levels above and below 3 g/day. Patients were followed for 1 year to collect survival and hospitalization data. Cox proportional hazards modeling was used to compare cardiac event-free survival between lycopene groups within each stratum of sodium intake. Higher lycopene intake was associated with longer cardiac event-free survival compared with lower lycopene intake (p = 0.003). The worst cardiac event-free survival was observed in the low lycopene intake group regardless of sodium intake (> 3 g/day HR = 3.01; p = 0.027 and ≤ 3 g/day HR= 3.34; p = 0.023). These findings suggest that increased lycopene intake has the potential to improve cardiac event-free survival in patients with HF independent of sodium intake.
Parenteral Nutrition and Intestinal Failure.

Science.gov (United States)

Bielawska, Barbara; Allard, Johane P

2017-05-06

Severe short bowel syndrome (SBS) is a major cause of chronic (Type 3) intestinal failure (IF) where structural and functional changes contribute to malabsorption and risk of micronutrient deficiencies. Chronic IF may be reversible, depending on anatomy and intestinal adaptation, but most patients require long-term nutritional support, generally in the form of parenteral nutrition (PN). SBS management begins with dietary changes and pharmacologic therapies taking into account individual anatomy and physiology, but these are rarely sufficient to avoid PN. New hormonal therapies targeting intestinal adaptation hold promise. Surgical options for SBS including intestinal transplant are available, but have significant limitations. Home PN (HPN) is therefore the mainstay of treatment for severe SBS. HPN involves chronic administration of macronutrients, micronutrients, fluid, and electrolytes via central venous access in the patient's home. HPN requires careful clinical and biochemical monitoring. Main complications of HPN are related to venous access (infection, thrombosis) and metabolic complications including intestinal failure associated liver disease (IFALD). Although HPN significantly impacts quality of life, outcomes are generally good and survival is mostly determined by the underlying disease. As chronic intestinal failure is a rare disease, registries are a promising strategy for studying HPN patients to improve outcomes.
ICDE project report on collection and analysis of common-cause failures of emergency diesel generators

International Nuclear Information System (INIS)

2001-02-01

This report documents a study performed on the set of common cause failures (CCF) of emergency diesel generators (EDG). The data studied here were derived from the International CCF Data Exchange (ICDE) database, to which several countries have submitted CCF event data. The data span a period from 1982 through 1997. The purpose of the ICDE is to allow multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses that include CCF modeling. Because CCF events are typically rare events, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, yields sufficient data for more rigorous analyses. This report is the result of an in-depth review of the EDG events and presents several insights about them. The objective of this document is to look beyond the CCF parameter estimates that can be obtained from the CCF data, to gain further understanding of why CCF events occur and what measures may be taken to prevent, or at least mitigate the effect of, EDG CCF events. The report presents details of the ICDE project, a quantitative presentation of the EDG events, and a discussion of some engineering aspects of the events. (authors)
Renal failure after treatment with interferon alpha 2b

NARCIS (Netherlands)

Roeloffzen, WWH; Hospers, GAP; De Vries, EGE; Navis, GJ

2002-01-01

Although there has been considerable experience with interferons in the treatment of malignancy and viral illnesses, acute renal failure as a side-effect of interferon treatment has rarely been reported. We present the case of a patient who developed acute on chronic renal failure 16 months after
Satellite failures revisited

Science.gov (United States)

Balcerak, Ernie

2012-12-01

In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.
When the heart kills the liver: acute liver failure in congestive heart failure

Directory of Open Access Journals (Sweden)

Saner FH

2009-12-01

Full Text Available Abstract Congestive heart failure as a cause of acute liver failure is rarely documented with only a few cases. Although the pathophysiology is poorly understood, there is rising evidence, that low cardiac output with consecutive reduction in hepatic blood flow is a main causing factor, rather than hypotension. In the setting of acute liver failure due to congestive heart failure, clinical signs of the latter can be absent, which requires an appropriate diagnostic approach. As a reference center for acute liver failure and liver transplantation we recorded from May 2003 to December 2007 202 admissions with the primary diagnoses acute liver failure. 13/202 was due to congestive heart failure, which was associated with a mortality rate of 54%. Leading cause of death was the underlying heart failure. Asparagine transaminase (AST, bilirubin, and international normalized ratio (INR did not differ significantly in surviving and deceased patients at admission. Despite both groups had signs of cardiogenic shock, the cardiac index (CI was significantly higher in the survival group on admission as compared with non-survivors (2.1 L/min/m2 vs. 1.6 L/min/m2, p = 0.04. Central venous - and pulmonary wedge pressure did not differ significantly. Remarkable improvement of liver function was recorded in the group, who recovered from cardiogenic shock. In conclusion, patients with acute liver failure require an appropriate diagnostic approach. Congestive heart failure should always be considered as a possible cause of acute liver failure.
Severe right heart failure in a patient with Grave's disease.

Science.gov (United States)

Xenopoulos, N P; Braden, G A; Applegate, R J

1996-11-01

This brief report presents a patient with isolated right heart failure and two rare underlying causes, hyperthyroidism and dysplastic tricuspid valve. Repair of the tricuspid valve and treatment of the hyperthyroidism were both essential for successful treatment of the right heart failure. Most important, recrudescence of hyperthyroidism in this patient was associated with reappearance of florid right heart failure. This report provides further information about a potential linkage of hyperthyroidism and severe right heart failure.
In silico assessment of biomedical products: The conundrum of rare but not so rare events in two case studies.

Science.gov (United States)

Viceconti, Marco; Cobelli, Claudio; Haddad, Tarek; Himes, Adam; Kovatchev, Boris; Palmer, Mark

2017-05-01

In silico clinical trials, defined as "The use of individualized computer simulation in the development or regulatory evaluation of a medicinal product, medical device, or medical intervention," have been proposed as a possible strategy to reduce the regulatory costs of innovation and the time to market for biomedical products. We review some of the the literature on this topic, focusing in particular on those applications where the current practice is recognized as inadequate, as for example, the detection of unexpected severe adverse events too rare to be detected in a clinical trial, but still likely enough to be of concern. We then describe with more details two case studies, two successful applications of in silico clinical trial approaches, one relative to the University of Virginia/Padova simulator that the Food and Drug Administration has accepted as possible replacement for animal testing in the preclinical assessment of artificial pancreas technologies, and the second, an investigation of the probability of cardiac lead fracture, where a Bayesian network was used to combine in vivo and in silico observations, suggesting a whole new strategy of in silico-augmented clinical trials, to be used to increase the numerosity where recruitment is impossible, or to explore patients' phenotypes that are unlikely to appear in the trial cohort, but are still frequent enough to be of concern.
An Infant with Splenohepatomegaly: A Rare Cause

Directory of Open Access Journals (Sweden)

Kathiravan Kalyanasundaram

2014-01-01

Full Text Available Osteopetrosis is a rare congenital disorder of bone resorption, caused by failure of osteoclasts to reabsorb immature bone. Malignant infantile osteopetrosis presents in early life with generalized osteosclerosis and decreased bone marrow spaces, resulting in anemia, splenohepatomegaly due to extramedullary hematopoiesis, cranial nerve compression, and growth failure. It is a fatal condition with death occurring within the first year of life. Bone marrow transplant remains the only curative treatment. We present a report of an infant with splenohepatomegaly, who was diagnosed with malignant infantile osteopetrosis.

Hyporesponsiveness to Darbepoetin Alfa in Patients With Heart Failure and Anemia in the RED-HF Study (Reduction of Events by Darbepoetin Alfa in Heart Failure): Clinical and Prognostic Associations.

Science.gov (United States)

van der Meer, Peter; Grote Beverborg, Niels; Pfeffer, Marc A; Olson, Kurt; Anand, Inder S; Westenbrink, B Daan; McMurray, John J V; Swedberg, Karl; Young, James B; Solomon, Scott D; van Veldhuisen, Dirk J

2018-02-01

A poor response to erythropoiesis-stimulating agents such as darbepoetin alfa has been associated with adverse outcomes in patients with diabetes mellitus, chronic kidney disease, and anemia; whether this is also true in heart failure is unclear. We performed a post hoc analysis of the RED-HF trial (Reduction of Events by Darbepoetin Alfa in Heart Failure), in which 1008 patients with systolic heart failure and anemia (hemoglobin level, 9.0-12.0 g/dL) were randomized to darbepoetin alfa. We examined the relationship between the hematopoietic response to darbepoetin alfa and the incidence of all-cause death or first heart failure hospitalization during a follow-up of 28 months. For the purposes of the present study, patients in the lowest quartile of hemoglobin change after 4 weeks were considered nonresponders. The median initial hemoglobin change in nonresponders (n=252) was -0.25 g/dL and +1.00 g/dL in the remainder of patients (n=756). Worse renal function, lower sodium levels, and less use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were independently associated with nonresponse. Although a low endogenous erythropoietin level helped to differentiate responders from nonresponders, its predictive value in a multivariable model was poor (C statistic=0.69). Nonresponders had a higher rate of all-cause death or first heart failure hospitalization (hazard ratio, 1.25; 95% confidence interval, 1.02-1.54) and a higher risk of all-cause mortality (hazard ratio, 1.30; 95% confidence interval, 1.04-1.63) than responders. A poor response to darbepoetin alfa was associated with worse outcomes in heart failure patients with anemia. Patients with a poor response were difficult to identify using clinical and biochemical biomarkers. URL: https://www.clinicaltrials.gov. Unique identifier: NCT00358215. © 2018 American Heart Association, Inc.
X-framework: Space system failure analysis framework

Science.gov (United States)

Newman, John Steven

Space program and space systems failures result in financial losses in the multi-hundred million dollar range every year. In addition to financial loss, space system failures may also represent the loss of opportunity, loss of critical scientific, commercial and/or national defense capabilities, as well as loss of public confidence. The need exists to improve learning and expand the scope of lessons documented and offered to the space industry project team. One of the barriers to incorporating lessons learned include the way in which space system failures are documented. Multiple classes of space system failure information are identified, ranging from "sound bite" summaries in space insurance compendia, to articles in journals, lengthy data-oriented (what happened) reports, and in some rare cases, reports that treat not only the what, but also the why. In addition there are periodically published "corporate crisis" reports, typically issued after multiple or highly visible failures that explore management roles in the failure, often within a politically oriented context. Given the general lack of consistency, it is clear that a good multi-level space system/program failure framework with analytical and predictive capability is needed. This research effort set out to develop such a model. The X-Framework (x-fw) is proposed as an innovative forensic failure analysis approach, providing a multi-level understanding of the space system failure event beginning with the proximate cause, extending to the directly related work or operational processes and upward through successive management layers. The x-fw focus is on capability and control at the process level and examines: (1) management accountability and control, (2) resource and requirement allocation, and (3) planning, analysis, and risk management at each level of management. The x-fw model provides an innovative failure analysis approach for acquiring a multi-level perspective, direct and indirect causation of
ICDE project report: collection and analysis of common-cause failure of check valves

International Nuclear Information System (INIS)

Theiss, Klaus; Hessel, Philippe; Werner, Wolfgang

2003-05-01

This report documents a study performed on the set of Common Cause Failure (CCF) events of Check Valves (CVs). The events studied here were derived from the International CCF Data Exchange (ICDE) database. Organizations from Canada, Finland, France, Germany, Netherlands, Sweden, Switzerland and the United States contributed with data to this data exchange. This study examines 94 CCF events of CVs reported in the ICDE database by tabulating the data and observing trends. The database contains general information about event attributes like root cause, coupling factor, detection method and corrective action taken. As part of this study, most of these events were reviewed in more detail and characterized by failure cause and failure symptom categories. The study itself begins with an overview of the entire data set in chapter 5. Charts are provided for each of the above-mentioned event attributes. This chapter forms the baseline for chapter 6. The intention of chapter 6 is to give the reader a deeper qualitative insight in the database content beyond that obtained from using the event coding only. Chapter 7 contains the summary of the study results and the conclusions derived from. Approximately 8% of all ICDE events of CVs were complete CCFs (all redundant components had failed). The number of partial CCF events (at least two of the redundant components failed) accounted for 24%. In the remaining 68% of the ICDE events, less than two components had failed completely, and the other components of the observed group only suffered from small defects, incipient degradation or were not affected at all. However, it was found that for more than 75% of the ICDE events the causal factors had a high probability to be shared by all the redundant components. 88 of the 94 reported ICDE events were reviewed in some more detail in Section 6 of this report with respect to failure causes, failure symptoms and failure mechanism. All events classified with a low 'shared cause factor
Recent insights from the international common-cause failure data exchange project

Energy Technology Data Exchange (ETDEWEB)

Kreuser, Albert [Gesellschaft fur Anlagen- und Reaktorsicherheit (GRS) gGmbH, Cologne (Germany); Johanson, Gunner [AF Industry, Stockholm (Sweden)

2017-03-15

Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE) project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) framework and has successfully been operated over six consecutive terms (the current term being 2015–2017). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers) and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.
Recent Insights from the International Common-Cause Failure Data Exchange Project

Directory of Open Access Journals (Sweden)

Albert Kreuser

2017-03-01

Full Text Available Common-cause failure (CCF events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD/Nuclear Energy Agency (NEA framework and has successfully been operated over six consecutive terms (the current term being 2015–2017. The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.
A Study of Failure Events in Drinking Water Systems As a Basis for Comparison and Evaluation of the Efficacy of Potable Reuse Schemes.

Science.gov (United States)

Onyango, Laura A; Quinn, Chloe; Tng, Keng H; Wood, James G; Leslie, Greg

2015-01-01

Potable reuse is implemented in several countries around the world to augment strained water supplies. This article presents a public health perspective on potable reuse by comparing the critical infrastructure and institutional capacity characteristics of two well-established potable reuse schemes with conventional drinking water schemes in developed nations that have experienced waterborne outbreaks. Analysis of failure events in conventional water systems between 2003 and 2013 showed that despite advances in water treatment technologies, drinking water outbreaks caused by microbial contamination were still frequent in developed countries and can be attributed to failures in infrastructure or institutional practices. Numerous institutional failures linked to ineffective treatment protocols, poor operational practices, and negligence were detected. In contrast, potable reuse schemes that use multiple barriers, online instrumentation, and operational measures were found to address the events that have resulted in waterborne outbreaks in conventional systems in the past decade. Syndromic surveillance has emerged as a tool in outbreak detection and was useful in detecting some outbreaks; increases in emergency department visits and GP consultations being the most common data source, suggesting potential for an increasing role in public health surveillance of waterborne outbreaks. These results highlight desirable characteristics of potable reuse schemes from a public health perspective with potential for guiding policy on surveillance activities.
GRAVES’ DISEASE INDUCED REVERSIBLE SEVERE RIGHT HEART FAILURE

Directory of Open Access Journals (Sweden)

Kathyayani

2015-07-01

Full Text Available A middle aged man presented with evidence of right - sided heart failure in atrial fibrillation (AF and was found to have severe Tricuspid Regurgitation (TR with pulmonary artery hypertension (PAH, with normal left ventricular function. The common possible seconda ry causes of PAH were ruled out, but during investigation he was found to have elevated thyroid function tests compatible with the diagnosis of Graves’ disease. The treatment of Graves’ disease was started with anti - thyroid drugs and associated with a sign ificant reduction in the pulmonary arterial pressure. This case report is presented to highlight one of the rare and underdiagnosed presentations of Graves’ disease. Thyrotoxicosis can present with profound cardiovascular complications. In recent times, th ere have been few reports of secondary PAH with TR in patients with hyperthyroidism. Previously asymptomatic Graves’ disease having the signs and symptoms of right heart failure is a rare presentation and the association could be easily missed. This case p resentation emphasizes that the diagnosis of thyroid heart disease with heart failure secondary to Graves’ disease should be considered in any patient regardless of age, gender with clinical features of heart failure of unknown etiology and timely initiation of anti - thyroid drugs is necessary to treat these reversible cardiac failures.
External events analysis for the Savannah River Site K reactor

International Nuclear Information System (INIS)

Brandyberry, M.D.; Wingo, H.E.

1990-01-01

The probabilistic external events analysis performed for the Savannah River Site K-reactor PRA considered many different events which are generally perceived to be ''external'' to the reactor and its systems, such as fires, floods, seismic events, and transportation accidents (as well as many others). Events which have been shown to be significant contributors to risk include seismic events, tornados, a crane failure scenario, fires and dam failures. The total contribution to the core melt frequency from external initiators has been found to be 2.2 x 10 -4 per year, from which seismic events are the major contributor (1.2 x 10 -4 per year). Fire initiated events contribute 1.4 x 10 -7 per year, tornados 5.8 x 10 -7 per year, dam failures 1.5 x 10 -6 per year and the crane failure scenario less than 10 -4 per year to the core melt frequency. 8 refs., 3 figs., 5 tabs
Hierarchical modeling for rare event detection and cell subset alignment across flow cytometry samples.

Directory of Open Access Journals (Sweden)

Andrew Cron

consistent labeling of cell subsets and increase the sensitivity of rare event detection in the context of quantifying antigen-specific immune responses.
Human based roots of failures in nuclear events investigations

Energy Technology Data Exchange (ETDEWEB)

Ziedelis, Stanislovas; Noel, Marc; Strucic, Miodrag [Commission of the European Communities, Petten (Netherlands). European Clearinghouse on Operational Experience Feedback for Nuclear Power Plants

2012-10-15

This paper aims for improvement of quality of the event investigations in the nuclear industry through analysis of the existing practices, identifying and removing the existing Human and Organizational Factors (HOF) and management related barriers. It presents the essential results of several studies performed by the European Clearinghouse on Operational Experience. Outcomes of studies are based on survey of currently existing event investigation practices typical for nuclear industry of 12 European countries, as well as on insights from analysis of numerous event investigation reports. System of operational experience feedback from information based on event investigation results is not enough effective to prevent and even to decrease frequency of recurring events due to existing methodological, HOF-related and/or knowledge management related constraints. Besides that, several latent root causes of unsuccessful event investigation are related to weaknesses in safety culture of personnel and managers. These weaknesses include focus on costs or schedule, political manipulation, arrogance, ignorance, entitlement and/or autocracy. Upgrades in safety culture of organization's personnel and its senior management especially seem to be an effective way to improvement. Increasing of competencies, capabilities and level of independency of event investigation teams, elaboration of comprehensive software, ensuring of positive approach, adequate support and impartiality of management could also facilitate for improvement of quality of the event investigations. (orig.)
Human based roots of failures in nuclear events investigations

International Nuclear Information System (INIS)

Ziedelis, Stanislovas; Noel, Marc; Strucic, Miodrag

2012-01-01

This paper aims for improvement of quality of the event investigations in the nuclear industry through analysis of the existing practices, identifying and removing the existing Human and Organizational Factors (HOF) and management related barriers. It presents the essential results of several studies performed by the European Clearinghouse on Operational Experience. Outcomes of studies are based on survey of currently existing event investigation practices typical for nuclear industry of 12 European countries, as well as on insights from analysis of numerous event investigation reports. System of operational experience feedback from information based on event investigation results is not enough effective to prevent and even to decrease frequency of recurring events due to existing methodological, HOF-related and/or knowledge management related constraints. Besides that, several latent root causes of unsuccessful event investigation are related to weaknesses in safety culture of personnel and managers. These weaknesses include focus on costs or schedule, political manipulation, arrogance, ignorance, entitlement and/or autocracy. Upgrades in safety culture of organization's personnel and its senior management especially seem to be an effective way to improvement. Increasing of competencies, capabilities and level of independency of event investigation teams, elaboration of comprehensive software, ensuring of positive approach, adequate support and impartiality of management could also facilitate for improvement of quality of the event investigations. (orig.)
Secondary scintillation yield of xenon with sub-percent levels of CO2 additive for rare-event detection

Science.gov (United States)

Henriques, C. A. O.; Freitas, E. D. C.; Azevedo, C. D. R.; González-Díaz, D.; Mano, R. D. P.; Jorge, M. R.; Fernandes, L. M. P.; Monteiro, C. M. B.; Gómez-Cadenas, J. J.; Álvarez, V.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carríon, J. V.; Cebrían, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Esteve, R.; Felkai, R.; Ferrario, P.; Ferreira, A. L.; Goldschmidt, A.; Gutiérrez, R. M.; Hauptman, J.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Jones, B. J. P.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; McDonald, A. D.; Monrabal, F.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Nygren, D. R.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; NEXT Collaboration

2017-10-01

Xe-CO2 mixtures are important alternatives to pure xenon in Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification with applications in the important field of rare event detection such as directional dark matter, double electron capture and double beta decay detection. The addition of CO2 to pure xenon at the level of 0.05-0.1% can reduce significantly the scale of electron diffusion from 10 mm /√{m} to 2.5 mm /√{m}, with high impact on the discrimination efficiency of the events through pattern recognition of the topology of primary ionization trails. We have measured the electroluminescence (EL) yield of Xe-CO2 mixtures, with sub-percent CO2 concentrations. We demonstrate that the EL production is still high in these mixtures, 70% and 35% relative to that produced in pure xenon, for CO2 concentrations around 0.05% and 0.1%, respectively. The contribution of the statistical fluctuations in EL production to the energy resolution increases with increasing CO2 concentration, being smaller than the contribution of the Fano factor for concentrations below 0.1% CO2.
Dependency models and probability of joint events

International Nuclear Information System (INIS)

Oerjasaeter, O.

1982-08-01

Probabilistic dependencies between components/systems are discussed with reference to a broad classification of potential failure mechanisms. Further, a generalized time-dependency model, based on conditional probabilities for estimation of the probability of joint events and event sequences is described. The applicability of this model is clarified/demonstrated by various examples. It is concluded that the described model of dependency is a useful tool for solving a variety of practical problems concerning the probability of joint events and event sequences where common cause and time-dependent failure mechanisms are involved. (Auth.)
Rare KL decays at Fermilab

International Nuclear Information System (INIS)

Schnetzer, St.

1997-01-01

Recent results and the future prospects for rare K L decay at Fermilab are described. A summary of all rare decay results from E799 Phase I (the 1991 run) are presented. Three new results: K L → e + e - μ + μ - , K L → π 0 μe, and π 0 → e + e - e + e - are discussed in detail. Improvements for KTeV (the 1996-1997 run) are discussed and the expected sensitivities listed. Finally, the KAMI program for rare decays with the Main Injector (2000 and beyond) is presented with emphasis on a search for the decay K L → π 0 νν-bar at O(10 -12 ) single-event-sensitivity. (author)
Management and outcomes following an acute coronary event in patients with chronic heart failure 1999-2007.

Science.gov (United States)

Ranasinghe, Isuru; Naoum, Chris; Aliprandi-Costa, Bernadette; Sindone, Andrew P; Steg, P Gabriel; Elliott, John; McGarity, Bruce; Lefkovits, Jeffrey; Brieger, David

2012-05-01

The outcome of patients with chronic heart failure (CHF) following an ischaemic event is poorly understood. We evaluated the management and outcomes of CHF patients presenting with an acute coronary syndrome (ACS) and explored changes in outcomes over time. A total of 5556 patients enrolled in the Australia-New Zealand population of the Global Registry of Acute Coronary Events (GRACE) between 1999 and 2007 were included. Patients with CHF (n = 609) were compared with those without CHF (n = 4947). Patients with CHF were on average 10 years older, were more likely to be female, had more co-morbidities and cardiac risk factors, and were more likely to have a prior history of angina, myocardial infarction, and revascularization by coronary artery bypass graft (CABG) when compared with those without CHF. CHF was associated with a substantial increase in in-hospital renal failure [odds ratio (OR) 1.76, 95% confidence interval (CI) 1.15-2.71], readmission post-discharge (OR 1.47, 95% CI 1.17-1.90), and 6-month mortality (OR 2.25, 95% CI 1.55-3.27). Over the 9 year study period, in-hospital and 6 month mortality in those with CHF declined by absolute rates of 7.5% and 14%, respectively. This was temporally associated with an increase in prescription of thienopyridines, beta-blockers, statins, and angiotensin II receptor blockers, increased rates of coronary angiography, and 31.8% absolute increase in referral rates for cardiac rehabilitation. Acute coronary syndrome patients with pre-existing CHF are a very high risk group and carry a disproportionate mortality burden. Encouragingly, there was a marked temporal improvement in outcomes over a 9 year period with an increase in evidence-based treatments and secondary preventative measures.
ES-RBE Event sequence reliability Benchmark exercise

International Nuclear Information System (INIS)

Poucet, A.E.J.

1991-01-01

The event Sequence Reliability Benchmark Exercise (ES-RBE) can be considered as a logical extension of the other three Reliability Benchmark Exercices : the RBE on Systems Analysis, the RBE on Common Cause Failures and the RBE on Human Factors. The latter, constituting Activity No. 1, was concluded by the end of 1987. The ES-RBE covered the techniques that are currently used for analysing and quantifying sequences of events starting from an initiating event to various plant damage states, including analysis of various system failures and/or successes, human intervention failure and/or success and dependencies between systems. By this way, one of the scopes of the ES-RBE was to integrate the experiences gained in the previous exercises
Low-temperature relative reflectivity measurements of reflective and scintillating foils used in rare event searches

Science.gov (United States)

Langenkämper, A.; Ulrich, A.; Defay, X.; Feilitzsch, F. v.; Lanfranchi, J.-C.; Mondragón, E.; Münster, A.; Oppenheimer, C.; Potzel, W.; Roth, S.; Schönert, S.; Steiger, H.; Trinh Thi, H. H.; Wawoczny, S.; Willers, M.; Zöller, A.

2018-03-01

In this work we investigate the reflectivity of highly reflective multilayer polymer foils used in the CRESST experiment. The CRESST experiment searches directly for dark matter via operating scintillating CaWO4 crystals as targets for elastic dark matter-nucleon scattering. In order to suppress background events, the experiment employs the so-called phonon-light technique which is based on the simultaneous measurement of the heat signal in the main CaWO4 target crystal and of the emitted scintillation light with a separate cryogenic light detector. Both detectors are surrounded by a highly reflective and scintillating multilayer polymer foil to increase the light collection efficiency and to veto surface backgrounds. While this study is motivated by the CRESST experiment, the results are also relevant for other rare event searches using scintillating cryogenic bolometers in the field of the search of dark matter and neutrinoless double beta decay (0 νββ). In this work a dedicated experiment has been set up to determine the relative reflectivity at 300 K and 20 K of three multilayer foils ("VM2000", "VM2002", "Vikuiti") produced by the company 3M. The intensity of a light beam reflected off the foil is measured with a CCD camera. The ratio of the intensities at 300 K and 20 K corresponds to the relative reflectivity change. The measurements performed in this work show no variation of the reflectivity with temperature at a level of ∼1%.
Decrease the Number of Glovebox Glove Breaches and Failures

Energy Technology Data Exchange (ETDEWEB)

Hurtle, Jackie C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2013-12-24

Los Alamos National Laboratory (LANL) is committed to the protection of the workers, public, and environment while performing work and uses gloveboxes as engineered controls to protect workers from exposure to hazardous materials while performing plutonium operations. Glovebox gloves are a weak link in the engineered controls and are a major cause of radiation contamination events which can result in potential worker exposure and localized contamination making operational areas off-limits and putting programmatic work on hold. Each day of lost opportunity at Technical Area (TA) 55, Plutonium Facility (PF) 4 is estimated at $1.36 million. Between July 2011 and June 2013, TA-55-PF-4 had 65 glovebox glove breaches and failures with an average of 2.7 per month. The glovebox work follows the five step safety process promoted at LANL with a decision diamond interjected for whether or not a glove breach or failure event occurred in the course of performing glovebox work. In the event that no glove breach or failure is detected, there is an additional decision for whether or not contamination is detected. In the event that contamination is detected, the possibility for a glove breach or failure event is revisited.
Common cause failure investigations using the European Reliability Data System

International Nuclear Information System (INIS)

Games, A.M.; Breewood, M.; Amendola, A.; Keller, A.Z.

1984-01-01

The European Reliability Data System (ERDS) has provided data for use in investigations into common cause failures (CCFs) in nuclear power plants. These investigations have been made on two levels, at a system and inter-system level. Data have been used from the Component Event Data Bank and from the Licensee Event Report Files, both part of the ERDS. The two studies required different methodologies although both commenced with a temporal sorting procedure for the failure events. The studies demonstrated that different types of common cause failure necessitate different search algorithms, and thus a data search must be closely related to an appropriate CCF classification system, which in the first instance would not be based on causes of failure. (author)
Pressure Effects Analysis of National Ignition Facility Capacitor Module Events

International Nuclear Information System (INIS)

Brereton, S; Ma, C; Newton, M; Pastrnak, J; Price, D; Prokosch, D

1999-01-01

Capacitors and power conditioning systems required for the National Ignition Facility (NIF) have experienced several catastrophic failures during prototype demonstration. These events generally resulted in explosion, generating a dramatic fireball and energetic shrapnel, and thus may present a threat to the walls of the capacitor bay that houses the capacitor modules. The purpose of this paper is to evaluate the ability of the capacitor bay walls to withstand the overpressure generated by the aforementioned events. Two calculations are described in this paper. The first one was used to estimate the energy release during a fireball event and the second one was used to estimate the pressure in a capacitor module during a capacitor explosion event. Both results were then used to estimate the subsequent overpressure in the capacitor bay where these events occurred. The analysis showed that the expected capacitor bay overpressure was less than the pressure tolerance of the walls. To understand the risk of the above events in NIF, capacitor module failure probabilities were also calculated. This paper concludes with estimates of the probability of single module failure and multi-module failures based on the number of catastrophic failures in the prototype demonstration facility

Estimation of initiating event frequency for external flood events by extreme value theorem

International Nuclear Information System (INIS)

Chowdhury, Sourajyoti; Ganguly, Rimpi; Hari, Vibha

2017-01-01

External flood is an important common cause initiating event in nuclear power plants (NPPs). It may potentially lead to severe core damage (SCD) by first causing the failure of the systems required for maintaining the heat sinks and then by contributing to failures of engineered systems designed to mitigate such failures. The sample NPP taken here is twin 220 MWe Indian standard pressurized heavy water reactor (PHWR) situated inland. A comprehensive in-house Level-1 internal event PSA for full power had already been performed. External flood assessment was further conducted in area of external hazard risk assessment in response to post-Fukushima measures taken in nuclear industries. The present paper describes the methodology to calculate initiating event (IE) frequency for external flood events for the sample inland Indian NPP. General extreme value (GEV) theory based on maximum likelihood method (MLM) and order statistics approach (OSA) is used to analyse the rainfall data for the site. Thousand-year return level and necessary return periods for extreme rainfall are evaluated. These results along with plant-specific topographical calculations quantitatively establish that external flooding resulting from upstream dam break, river flooding and heavy rainfall (flash flood) would be unlikely for the sample NPP in consideration.
A Bivariate return period for levee failure monitoring

Science.gov (United States)

Isola, M.; Caporali, E.

2017-12-01

Levee breaches are strongly linked with the interaction processes among water, soil and structure, thus many are the factors that affect the breach development. One of the main is the hydraulic load, characterized by intensity and duration, i.e. by the flood event hydrograph. On the magnitude of the hydraulic load is based the levee design, generally without considering the fatigue failure due to the load duration. Moreover, many are the cases in which the levee breach are characterized by flood of magnitude lower than the design one. In order to implement the strategies of flood risk management, we built here a procedure based on a multivariate statistical analysis of flood peak and volume together with the analysis of the past levee failure events. Particularly, in order to define the probability of occurrence of the hydraulic load on a levee, a bivariate copula model is used to obtain the bivariate joint distribution of flood peak and volume. Flood peak is the expression of the load magnitude, while the volume is the expression of the stress over time. We consider the annual flood peak and the relative volume. The volume is given by the hydrograph area between the beginning and the end of event. The beginning of the event is identified as an abrupt rise of the discharge by more than 20%. The end is identified as the point from which the receding limb is characterized by the baseflow, using a nonlinear reservoir algorithm as baseflow separation technique. By this, with the aim to define warning thresholds we consider the past levee failure events and the relative bivariate return period (BTr) compared with the estimation of a traditional univariate model. The discharge data of 30 hydrometric stations of Arno River in Tuscany, Italy, in the period 1995-2016 are analysed. The database of levee failure events, considering for each event the location as well as the failure mode, is also created. The events were registered in the period 2000-2014 by EEA
Immune mediated liver failure.

Science.gov (United States)

Wang, Xiaojing; Ning, Qin

2014-01-01

Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capacity. Direct damage and immune-mediated liver injury are two major factors involved in this process. Increasing evidence has suggested the essential role of immune-mediated liver injury in the pathogenesis of liver failure. Here, we review the evolved concepts concerning the mechanisms of immune-mediated liver injury in liver failure from human and animal studies. Both innate and adaptive immunity, especially the interaction of various immune cells and molecules as well as death receptor signaling system are discussed. In addition, we highlight the concept of "immune coagulation", which has been shown to be related to the disease progression and liver injury exacerbation in HBV related acute-on-chronic liver failure.
Uncertainty analysis of reactor safety systems with statistically correlated failure data

International Nuclear Information System (INIS)

Dezfuli, H.; Modarres, M.

1985-01-01

The probability of occurrence of the top event of a fault tree is estimated from failure probability of components that constitute the fault tree. Component failure probabilities are subject to statistical uncertainties. In addition, there are cases where the failure data are statistically correlated. Most fault tree evaluations have so far been based on uncorrelated component failure data. The subject of this paper is the description of a method of assessing the probability intervals for the top event failure probability of fault trees when component failure data are statistically correlated. To estimate the mean and variance of the top event, a second-order system moment method is presented through Taylor series expansion, which provides an alternative to the normally used Monte-Carlo method. For cases where component failure probabilities are statistically correlated, the Taylor expansion terms are treated properly. A moment matching technique is used to obtain the probability distribution function of the top event through fitting a Johnson Ssub(B) distribution. The computer program (CORRELATE) was developed to perform the calculations necessary for the implementation of the method developed. The CORRELATE code is very efficient and consumes minimal computer time. This is primarily because it does not employ the time-consuming Monte-Carlo method. (author)
Meta-Analysis of the Associations of p-Cresyl Sulfate (PCS) and Indoxyl Sulfate (IS) with Cardiovascular Events and All-Cause Mortality in Patients with Chronic Renal Failure.

Science.gov (United States)

Lin, Cheng-Jui; Wu, Vincent; Wu, Pei-Chen; Wu, Chih-Jen

2015-01-01

Indoxyl sulfate (IS) and p-cresyl sulfate (PCS) are protein-bound uremic toxins that increase in the sera of patients with chronic kidney disease (CKD), and are not effectively removed by dialysis. The purpose of this meta-analysis was to investigate the relationships of PCS and IS with cardiovascular events and all-cause mortality in patients with CKD stage 3 and above. Medline, Cochrane, and EMBASE databases were searched until January 1, 2014 with combinations of the following keywords: chronic renal failure, end-stage kidney disease, uremic toxin, uremic retention, indoxyl sulfate, p-cresyl sulfate. Inclusion criteria were: 1) Patients with stage 1 to 5 CKD; 2) Prospective study; 3) Randomized controlled trial; 4) English language publication. The associations between serum levels of PCS and IS and the risks of all-cause mortality and cardiovascular events were the primary outcome measures. Of 155 articles initially identified, 10 prospective and one cross-sectional study with a total 1,572 patients were included. Free PCS was significantly associated with all-cause mortality among patients with chronic renal failure (pooled OR = 1.16, 95% CI = 1.03 to 1.30, P = 0.013). An elevated free IS level was also significantly associated with increased risk of all-cause mortality (pooled OR = 1.10, 95% CI = 1.03 to 1.17, P = 0.003). An elevated free PCS level was significantly associated with an increased risk of cardiovascular events among patients with chronic renal failure (pooled OR = 1.28, 95% CI = 1.10 to 1.50, P = 0.002), while free IS was not significantly associated with risk of cardiovascular events (pooled OR = 1.05, 95% CI = 0.98 to 1.13, P = 0.196). Elevated levels of PCS and IS are associated with increased mortality in patients with CKD, while PCS, but not IS, is associated with an increased risk of cardiovascular events.
Two Cases of Arnold-Chiari Malformation with Respiratory Failure

Directory of Open Access Journals (Sweden)

Sinem Iliaz

2014-03-01

Full Text Available Arnold–Chiari malformation is defined as downward displacement of the brainstem and cerebellum through the foramen magnum. It has different clinical presentations and four subtypes. It is known that downward migration of posterior fossa components through the foramen magnum and associated lower cranial nerve palsy and brainstem compression can cause respiratory failure. Acute respiratory failure could mark the onset of the disease. Posterior fossa decompression performed to treat primary disease can improve the central sleep abnormalities. As respiratory failure is rarely seen, this paper presents two cases of Arnold–Chiari malformation with respiratory failure.
Failure Forecasting in Triaxially Stressed Sandstones

Science.gov (United States)

Crippen, A.; Bell, A. F.; Curtis, A.; Main, I. G.

2017-12-01

Precursory signals to fracturing events have been observed to follow power-law accelerations in spatial, temporal, and size distributions leading up to catastrophic failure. In previous studies this behavior was modeled using Voight's relation of a geophysical precursor in order to perform `hindcasts' by solving for failure onset time. However, performing this analysis in retrospect creates a bias, as we know an event happened, when it happened, and we can search data for precursors accordingly. We aim to remove this retrospective bias, thereby allowing us to make failure forecasts in real-time in a rock deformation laboratory. We triaxially compressed water-saturated 100 mm sandstone cores (Pc= 25MPa, Pp = 5MPa, σ = 1.0E-5 s-1) to the point of failure while monitoring strain rate, differential stress, AEs, and continuous waveform data. Here we compare the current `hindcast` methods on synthetic and our real laboratory data. We then apply these techniques to increasing fractions of the data sets to observe the evolution of the failure forecast time with precursory data. We discuss these results as well as our plan to mitigate false positives and minimize errors for real-time application. Real-time failure forecasting could revolutionize the field of hazard mitigation of brittle failure processes by allowing non-invasive monitoring of civil structures, volcanoes, and possibly fault zones.
Prediction of accident sequence probabilities in a nuclear power plant due to earthquake events

International Nuclear Information System (INIS)

Hudson, J.M.; Collins, J.D.

1980-01-01

This paper presents a methodology to predict accident probabilities in nuclear power plants subject to earthquakes. The resulting computer program accesses response data to compute component failure probabilities using fragility functions. Using logical failure definitions for systems, and the calculated component failure probabilities, initiating event and safety system failure probabilities are synthesized. The incorporation of accident sequence expressions allows the calculation of terminal event probabilities. Accident sequences, with their occurrence probabilities, are finally coupled to a specific release category. A unique aspect of the methodology is an analytical procedure for calculating top event probabilities based on the correlated failure of primary events
A review for identification of initiating events in event tree development process on nuclear power plants

International Nuclear Information System (INIS)

Riyadi, Eko H.

2014-01-01

Initiating event is defined as any event either internal or external to the nuclear power plants (NPPs) that perturbs the steady state operation of the plant, if operating, thereby initiating an abnormal event such as transient or loss of coolant accident (LOCA) within the NPPs. These initiating events trigger sequences of events that challenge plant control and safety systems whose failure could potentially lead to core damage or large early release. Selection for initiating events consists of two steps i.e. first step, definition of possible events, such as by evaluating a comprehensive engineering, and by constructing a top level logic model. Then the second step, grouping of identified initiating event's by the safety function to be performed or combinations of systems responses. Therefore, the purpose of this paper is to discuss initiating events identification in event tree development process and to reviews other probabilistic safety assessments (PSA). The identification of initiating events also involves the past operating experience, review of other PSA, failure mode and effect analysis (FMEA), feedback from system modeling, and master logic diagram (special type of fault tree). By using the method of study for the condition of the traditional US PSA categorization in detail, could be obtained the important initiating events that are categorized into LOCA, transients and external events
Acute renal failure with sodium-glucose-cotransporter-2 inhibitors: Analysis of the FDA adverse event report system database.

Science.gov (United States)

Perlman, A; Heyman, S N; Matok, I; Stokar, J; Muszkat, M; Szalat, A

2017-12-01

Sodium-glucose-cotransporter-2 (SGLT2) inhibitors have recently been approved for the treatment of type II diabetes mellitus (T2DM). It has been proposed that these agents could induce acute renal failure (ARF) under certain conditions. This study aimed to evaluate the association between SGLT2-inhibitors and ARF in the FDA adverse event report system (FAERS) database. We analyzed adverse event cases submitted to FAERS between January 2013 and September 2016. ARF cases were identified using a structured medical query. Medications were identified using both brand and generic names. During the period evaluated, 18,915 reports (out of a total of 3,832,015 registered in FAERS) involved the use of SGLT2-inhibitors. SGLT2-inhibitors were reportedly associated with ARF in 1224 of these cases (6.4%), and were defined as the "primary" or "secondary" cause of the adverse event in 96.8% of these cases. The proportion of reports with ARF among reports with SGLT2 inhibitor was almost three-fold higher compared to reports without these drugs (ROR 2.88, 95% CI 2.71-3.05, p SGLT2-inhibitors was significantly greater than the proportion of ARF among cases with T2DM without SGLT2-inhibitors (ROR 1.68, 95% CI 1.57-1.8, p SGLT2-inhibitors, canagliflozin was associated with a higher proportion of reports of renal failure (7.3%), compared to empagliflozin and dapagliflozin (4.7% and 4.8% respectively, p SGLT2-inhibitors are associated with an increase in the proportion of reports of ARF compared to other medications. SGLT2-inhibitor agents may differ from one another in their respective risk for ARF. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.
Neonatal Bartter syndrome with cholelithiasis and hydrocephalus: Rare association.

Science.gov (United States)

Özdemir, Özmert Ma; Çıralı, Ceren; Yılmaz Ağladıoğlu, Sebahat; Evrengül, Havva; Tepeli, Emre; Ergin, Hacer

2016-09-01

Neonatal Bartter syndrome (NBS) is a rare autosomal recessive renal tubular disorder. This disease is characterized by hypokalemia, hypochloremia, and metabolic alkalosis that is often associated with failure to thrive and recurrent episodes of dehydration. The combination of BS and cholelithiasis in an infant is very rare. Herein, we report a premature male infant with NBS who developed cholelithiasis and hydrocephalus on clinical follow up. We recommend that periodic routine hepatobiliary ultrasonograpic screening for cholelithiasis should be performed in patients with NBS. © 2016 Japan Pediatric Society.
Study of a spherical gaseous detector for research of rare events at low energy threshold

International Nuclear Information System (INIS)

Dastgheibi-Fard, Ali

2014-01-01

The Spherical gaseous detector (or Spherical Proportional Counter, SPC) is a novel type of a particle detector, with a broad range of applications. Its main features include a very low energy threshold which is independent of the volume (due to its very low capacitance), a good energy resolution, robustness and a single detection readout channel. SEDINE, a low background detector installed at the underground site of Laboratoire Souterrain de Modane is currently being operated and aims at measuring events at a very low energy threshold, around 40 eV. The sensitivity for the rare events detection at low energy is correlated to the detector background and to the decreasing the level of energy threshold, which was the main point of this thesis. A major effort has been devoted to the operating of the experimental detector. Several detection parameters were optimized: the electric field homogeneity in the sphere, keeping clear of sparks, the electronic noise level and the leak rate of the detector. The detector is optimized for operation with a high pressure stable gain. The modification of the shield, cleanings of the detector and the addition of an anti-Radon tent have significantly reduced the background of SEDINE. Progress has increased the sensitivity of the detector at low energy up to a value comparable to the results other underground research experiences for the low mass WIMPs. We will present the results with a measured background in the region of keV, which has allowed us to show a competitive figure of exclusion for the production of light dark matter. (author) [fr
Safety relevant failure mechanisms in the post-operational phase

International Nuclear Information System (INIS)

Mayer, Gerhard; Stiller, Jan Christopher; Roemer, Sarah

2017-03-01

. Finally, national and international operating experience was evaluated with the aim to derive general failure mechanisms from events that have occurred. For this purpose, the database of German reportable events (VERA), the database of the OECD/NEA ''International Common-cause Data Exchange (ICDE)'' project as well as the database of the ''International Reporting Systems for Operating Experience (IRS)'' of the IAEA was searched. As these data sources comprise a total number of about 12,000 events, initially the evaluation focused on the 309 events that occurred in plants that are in the post operation or decommissioning phase. In order to capture events from power operation whose damage phenomena have special relevance for post operation, too, attempts were made to develop automatic searches that would deliver a pre-selection of relevant results. To evaluate this method, 900 events from a German twin unit plant over a period from their construction until the present were analysed manually. It turned out that an automated search did not deliver enveloping results. All in all, 12 events from German plants in post operation or decommissioning and 36 events from plants with power operation licences as well as 6 events from international operating experience (IRS and ICDE) which showed a failure mechanism with special relevance for the post operation phase were identified. The events were presented individually, with special emphasis on the description of the failure mechanism that was particularly relevant for post operation. The failure mechanisms identified can be allocated to the following three general categories: special operating modes; changed operating or ambient conditions; organisational and personnel boundary conditions. The failure mechanisms assigned to these categories are presented in a summarized form and discussed.
Automated Testing of Event-Driven Applications

DEFF Research Database (Denmark)

Jensen, Casper Svenning

may be tested by selecting an interesting input (i.e. a sequence of events), and deciding if a failure occurs when the selected input is applied to the event-driven application under test. Automated testing promises to reduce the workload for developers by automatically selecting interesting inputs...... and detect failures. However, it is non-trivial to conduct automated testing of event-driven applications because of, for example, infinite input spaces and the absence of specifications of correct application behavior. In this PhD dissertation, we identify a number of specific challenges when conducting...... automated testing of event-driven applications, and we present novel techniques for solving these challenges. First, we present an algorithm for stateless model-checking of event-driven applications with partial-order reduction, and we show how this algorithm may be used to systematically test web...
Probabilistic safety analysis for fire events for the NPP Isar 2

International Nuclear Information System (INIS)

Schmaltz, H.; Hristodulidis, A.

2007-01-01

The 'Probabilistic Safety Analysis for Fire Events' (Fire-PSA KKI2) for the NPP Isar 2 was performed in addition to the PSA for full power operation and considers all possible events which can be initiated due to a fire. The aim of the plant specific Fire-PSA was to perform a quantitative assessment of fire events during full power operation, which is state of the art. Based on simplistic assumptions referring to the fire induced failures, the influence of system- and component-failures on the frequency of the core damage states was analysed. The Fire-PSA considers events, which will result due to fire-induced failures of equipment on the one hand in a SCRAM and on the other hand in events, which will not have direct operational effects but because of the fire-induced failure of safety related installations the plant will be shut down as a precautionary measure. These events are considered because they may have a not negligible influence on the frequency of core damage states in case of failures during the plant shut down because of the reduced redundancy of safety related systems. (orig.)
Predictors of incident heart failure in patients after an acute coronary syndrome: The LIPID heart failure risk-prediction model.

Science.gov (United States)

Driscoll, Andrea; Barnes, Elizabeth H; Blankenberg, Stefan; Colquhoun, David M; Hunt, David; Nestel, Paul J; Stewart, Ralph A; West, Malcolm J; White, Harvey D; Simes, John; Tonkin, Andrew

2017-12-01

Coronary heart disease is a major cause of heart failure. Availability of risk-prediction models that include both clinical parameters and biomarkers is limited. We aimed to develop such a model for prediction of incident heart failure. A multivariable risk-factor model was developed for prediction of first occurrence of heart failure death or hospitalization. A simplified risk score was derived that enabled subjects to be grouped into categories of 5-year risk varying from 20%. Among 7101 patients from the LIPID study (84% male), with median age 61years (interquartile range 55-67years), 558 (8%) died or were hospitalized because of heart failure. Older age, history of claudication or diabetes mellitus, body mass index>30kg/m 2 , LDL-cholesterol >2.5mmol/L, heart rate>70 beats/min, white blood cell count, and the nature of the qualifying acute coronary syndrome (myocardial infarction or unstable angina) were associated with an increase in heart failure events. Coronary revascularization was associated with a lower event rate. Incident heart failure increased with higher concentrations of B-type natriuretic peptide >50ng/L, cystatin C>0.93nmol/L, D-dimer >273nmol/L, high-sensitivity C-reactive protein >4.8nmol/L, and sensitive troponin I>0.018μg/L. Addition of biomarkers to the clinical risk model improved the model's C statistic from 0.73 to 0.77. The net reclassification improvement incorporating biomarkers into the clinical model using categories of 5-year risk was 23%. Adding a multibiomarker panel to conventional parameters markedly improved discrimination and risk classification for future heart failure events. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.
Uncertainties and quantification of common cause failure rates and probabilities for system analyses

International Nuclear Information System (INIS)

Vaurio, Jussi K.

2005-01-01

Simultaneous failures of multiple components due to common causes at random times are modelled by constant multiple-failure rates. A procedure is described for quantification of common cause failure (CCF) basic event probabilities for system models using plant-specific and multiple-plant failure-event data. Methodology is presented for estimating CCF-rates from event data contaminated with assessment uncertainties. Generalised impact vectors determine the moments for the rates of individual systems or plants. These moments determine the effective numbers of events and observation times to be input to a Bayesian formalism to obtain plant-specific posterior CCF-rates. The rates are used to determine plant-specific common cause event probabilities for the basic events of explicit fault tree models depending on test intervals, test schedules and repair policies. Three methods are presented to determine these probabilities such that the correct time-average system unavailability can be obtained with single fault tree quantification. Recommended numerical values are given and examples illustrate different aspects of the methodology
Dispersed Trading and the Prevention of Market Failure

DEFF Research Database (Denmark)

Porter, David C.; Tanggaard, Carsten; G. Weaver, Daniel

With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight into thi......With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight...... combined with widely dispersed trading locations may be a viable means of protection against market failure during massive power disruptions or terrorist attacks....
Reliability of piping system components. Framework for estimating failure parameters from service data

International Nuclear Information System (INIS)

Nyman, R.; Hegedus, D.; Tomic, B.; Lydell, B.

1997-12-01

This report summarizes results and insights from the final phase of a R and D project on piping reliability sponsored by the Swedish Nuclear Power Inspectorate (SKI). The technical scope includes the development of an analysis framework for estimating piping reliability parameters from service data. The R and D has produced a large database on the operating experience with piping systems in commercial nuclear power plants worldwide. It covers the period 1970 to the present. The scope of the work emphasized pipe failures (i.e., flaws/cracks, leaks and ruptures) in light water reactors (LWRs). Pipe failures are rare events. A data reduction format was developed to ensure that homogenous data sets are prepared from scarce service data. This data reduction format distinguishes between reliability attributes and reliability influence factors. The quantitative results of the analysis of service data are in the form of conditional probabilities of pipe rupture given failures (flaws/cracks, leaks or ruptures) and frequencies of pipe failures. Finally, the R and D by SKI produced an analysis framework in support of practical applications of service data in PSA. This, multi-purpose framework, termed 'PFCA'-Pipe Failure Cause and Attribute- defines minimum requirements on piping reliability analysis. The application of service data should reflect the requirements of an application. Together with raw data summaries, this analysis framework enables the development of a prior and a posterior pipe rupture probability distribution. The framework supports LOCA frequency estimation, steam line break frequency estimation, as well as the development of strategies for optimized in-service inspection strategies
Reliability of piping system components. Framework for estimating failure parameters from service data

Energy Technology Data Exchange (ETDEWEB)

Nyman, R [Swedish Nuclear Power Inspectorate, Stockholm (Sweden); Hegedus, D; Tomic, B [ENCONET Consulting GesmbH, Vienna (Austria); Lydell, B [RSA Technologies, Vista, CA (United States)

1997-12-01

This report summarizes results and insights from the final phase of a R and D project on piping reliability sponsored by the Swedish Nuclear Power Inspectorate (SKI). The technical scope includes the development of an analysis framework for estimating piping reliability parameters from service data. The R and D has produced a large database on the operating experience with piping systems in commercial nuclear power plants worldwide. It covers the period 1970 to the present. The scope of the work emphasized pipe failures (i.e., flaws/cracks, leaks and ruptures) in light water reactors (LWRs). Pipe failures are rare events. A data reduction format was developed to ensure that homogenous data sets are prepared from scarce service data. This data reduction format distinguishes between reliability attributes and reliability influence factors. The quantitative results of the analysis of service data are in the form of conditional probabilities of pipe rupture given failures (flaws/cracks, leaks or ruptures) and frequencies of pipe failures. Finally, the R and D by SKI produced an analysis framework in support of practical applications of service data in PSA. This, multi-purpose framework, termed `PFCA`-Pipe Failure Cause and Attribute- defines minimum requirements on piping reliability analysis. The application of service data should reflect the requirements of an application. Together with raw data summaries, this analysis framework enables the development of a prior and a posterior pipe rupture probability distribution. The framework supports LOCA frequency estimation, steam line break frequency estimation, as well as the development of strategies for optimized in-service inspection strategies. 63 refs, 30 tabs, 22 figs.

A huge bladder calculus causing acute renal failure.

Science.gov (United States)

Komeya, Mitsuru; Sahoda, Tamami; Sugiura, Shinpei; Sawada, Takuto; Kitami, Kazuo

2013-02-01

A 81-year-old male was referred to our emergency outpatient unit due to acute renal failure. The level of serum creatinine was 276 μmol/l. A CT scan showed bilateral hydronephroureter, large bladder stone (7 cm × 6 cm × 6 cm) and bladder wall thickness. He was diagnosed as post renal failure due to bilateral hydronephroureter. Large bladder stone is thought to be the cause of bilateral hydronephroureter and renal failure. To improve renal failure, we performed open cystolithotomy and urethral catheterization. Three days after the surgery, the level of serum creatinine decreased to 224 μmol/l. He was discharged from our hospital with uneventful course. Bladder calculus is thought to be a rare cause of renal failure. We summarize the characteristics of bladder calculus causing renal failure. We should keep that long-term pyuria and urinary symptom, and repeated urinary tract infection can cause huge bladder calculus and renal failure in mind.
Lipid disorders in patients with renal failure: Role in cardiovascular events and progression of chronic kidney disease

Directory of Open Access Journals (Sweden)

Luca Visconti

2016-12-01

Full Text Available The spectrum of lipid disorders in chronic kidney disease (CKD is usually characterized by high triglycerides and reduced high dense lipoprotein (HDL, associated with normal or slightly reduced low dense lipoprotein (LDL-cholesterol. This dyslipidemia is associated with an increased risk for atherosclerotic cardiovascular disease. Keys for the cardiovascular risk reduction in these patients are lowering the number and modifying the composition of the cholesterol-carrying atherogenic lipoprotein particles. Statins have an important role in primary prevention of cardiovascular events and mortality in non-hemodialyzed CKD patients. The benefits in terms of progression of renal failure are contradictory. Patient education regarding dietary regimen should be part of the CKD clinical management.
Transplantation for acute liver failure in patients exposed to NSAIDs or paracetamol (acetaminophen): the multinational case-population SALT study.

Science.gov (United States)

Gulmez, Sinem Ezgi; Larrey, Dominique; Pageaux, Georges-Philippe; Lignot, Severine; Lassalle, Régis; Jové, Jérémy; Gatta, Angelo; McCormick, P Aiden; Metselaar, Harold J; Monteiro, Estela; Thorburn, Douglas; Bernal, William; Zouboulis-Vafiadis, Irene; de Vries, Corinne; Perez-Gutthann, Susana; Sturkenboom, Miriam; Bénichou, Jacques; Montastruc, Jean-Louis; Horsmans, Yves; Salvo, Francesco; Hamoud, Fatima; Micon, Sophie; Droz-Perroteau, Cécile; Blin, Patrick; Moore, Nicholas

2013-02-01

Most NSAIDs are thought to be able to cause hepatic injury and acute liver failure (ALF), but the event rates of those leading to transplantation (ALFT) remain uncertain. The aim of the study was to estimate population event rates for NSAID-associated ALFT METHODS: This was a case-population study of ALFT in 57 eligible liver transplant centres in seven countries (France, Greece, Ireland, Italy, The Netherlands, Portugal and the UK). Cases were all adults registered from 2005 to 2007 for a liver transplant following ALFT without identified clinical aetiology, exposed to an NSAID or paracetamol (acetaminophen) within 30 days before the onset of clinical symptoms. NSAID and paracetamol population exposures were assessed using national sales data from Intercontinental Marketing Services (IMS). Risk was estimated as the rate of ALFT per million treatment-years (MTY). In the 52 participating centres, 9479 patients were registered for transplantation, with 600 for ALFT, 301 of whom, without clinical aetiology, had been exposed to a drug within 30 days. Of these 301 patients, 40 had been exposed to an NSAID and 192 to paracetamol (81 of whom were without overdose). Event rates per MTY were 1.59 (95 % CI 1.1-2.2) for all NSAIDs pooled, 2.3 (95 % CI 1.2-3.9) for ibuprofen, 1.9 (95 % CI 0.8-3.7) for nimesulide, 1.6 (95 % CI 0.6-3.4) for diclofenac and 1.6 (95 % CI 0.3-4.5) for ketoprofen. For paracetamol, the event rate was 3.3 per MTY (95 % CI 2.6-4.1) without overdoses and 7.8 (95 % CI 6.8-9.0) including overdoses. ALF leading to registration for transplantation after exposure to an NSAID was rare, with no major difference between NSAID. Non-overdose paracetamol-exposed liver failure was twice more common than NSAID-exposed liver failure.
Bias correction of risk estimates in vaccine safety studies with rare adverse events using a self-controlled case series design.

Science.gov (United States)

Zeng, Chan; Newcomer, Sophia R; Glanz, Jason M; Shoup, Jo Ann; Daley, Matthew F; Hambidge, Simon J; Xu, Stanley

2013-12-15

The self-controlled case series (SCCS) method is often used to examine the temporal association between vaccination and adverse events using only data from patients who experienced such events. Conditional Poisson regression models are used to estimate incidence rate ratios, and these models perform well with large or medium-sized case samples. However, in some vaccine safety studies, the adverse events studied are rare and the maximum likelihood estimates may be biased. Several bias correction methods have been examined in case-control studies using conditional logistic regression, but none of these methods have been evaluated in studies using the SCCS design. In this study, we used simulations to evaluate 2 bias correction approaches-the Firth penalized maximum likelihood method and Cordeiro and McCullagh's bias reduction after maximum likelihood estimation-with small sample sizes in studies using the SCCS design. The simulations showed that the bias under the SCCS design with a small number of cases can be large and is also sensitive to a short risk period. The Firth correction method provides finite and less biased estimates than the maximum likelihood method and Cordeiro and McCullagh's method. However, limitations still exist when the risk period in the SCCS design is short relative to the entire observation period.
Probability estimation of rare extreme events in the case of small samples: Technique and examples of analysis of earthquake catalogs

Science.gov (United States)

Pisarenko, V. F.; Rodkin, M. V.; Rukavishnikova, T. A.

2017-11-01

The most general approach to studying the recurrence law in the area of the rare largest events is associated with the use of limit law theorems of the theory of extreme values. In this paper, we use the Generalized Pareto Distribution (GPD). The unknown GPD parameters are typically determined by the method of maximal likelihood (ML). However, the ML estimation is only optimal for the case of fairly large samples (>200-300), whereas in many practical important cases, there are only dozens of large events. It is shown that in the case of a small number of events, the highest accuracy in the case of using the GPD is provided by the method of quantiles (MQs). In order to illustrate the obtained methodical results, we have formed the compiled data sets characterizing the tails of the distributions for typical subduction zones, regions of intracontinental seismicity, and for the zones of midoceanic (MO) ridges. This approach paves the way for designing a new method for seismic risk assessment. Here, instead of the unstable characteristics—the uppermost possible magnitude M max—it is recommended to use the quantiles of the distribution of random maxima for a future time interval. The results of calculating such quantiles are presented.
Statin-associated muscular and renal adverse events: data mining of the public version of the FDA adverse event reporting system.

Directory of Open Access Journals (Sweden)

Toshiyuki Sakaeda

Full Text Available OBJECTIVE: Adverse event reports (AERs submitted to the US Food and Drug Administration (FDA were reviewed to assess the muscular and renal adverse events induced by the administration of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA reductase inhibitors (statins and to attempt to determine the rank-order of the association. METHODS: After a revision of arbitrary drug names and the deletion of duplicated submissions, AERs involving pravastatin, simvastatin, atorvastatin, or rosuvastatin were analyzed. Authorized pharmacovigilance tools were used for quantitative detection of signals, i.e., drug-associated adverse events, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean. Myalgia, rhabdomyolysis and an increase in creatine phosphokinase level were focused on as the muscular adverse events, and acute renal failure, non-acute renal failure, and an increase in blood creatinine level as the renal adverse events. RESULTS: Based on 1,644,220 AERs from 2004 to 2009, signals were detected for 4 statins with respect to myalgia, rhabdomyolysis, and an increase in creatine phosphokinase level, but these signals were stronger for rosuvastatin than pravastatin and atorvastatin. Signals were also detected for acute renal failure, though in the case of atorvastatin, the association was marginal, and furthermore, a signal was not detected for non-acute renal failure or for an increase in blood creatinine level. CONCLUSIONS: Data mining of the FDA's adverse event reporting system, AERS, is useful for examining statin-associated muscular and renal adverse events. The data strongly suggest the necessity of well-organized clinical studies with respect to statin-associated adverse events.
Statin-associated muscular and renal adverse events: data mining of the public version of the FDA adverse event reporting system.

Science.gov (United States)

Sakaeda, Toshiyuki; Kadoyama, Kaori; Okuno, Yasushi

2011-01-01

Adverse event reports (AERs) submitted to the US Food and Drug Administration (FDA) were reviewed to assess the muscular and renal adverse events induced by the administration of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) and to attempt to determine the rank-order of the association. After a revision of arbitrary drug names and the deletion of duplicated submissions, AERs involving pravastatin, simvastatin, atorvastatin, or rosuvastatin were analyzed. Authorized pharmacovigilance tools were used for quantitative detection of signals, i.e., drug-associated adverse events, including the proportional reporting ratio, the reporting odds ratio, the information component given by a Bayesian confidence propagation neural network, and the empirical Bayes geometric mean. Myalgia, rhabdomyolysis and an increase in creatine phosphokinase level were focused on as the muscular adverse events, and acute renal failure, non-acute renal failure, and an increase in blood creatinine level as the renal adverse events. Based on 1,644,220 AERs from 2004 to 2009, signals were detected for 4 statins with respect to myalgia, rhabdomyolysis, and an increase in creatine phosphokinase level, but these signals were stronger for rosuvastatin than pravastatin and atorvastatin. Signals were also detected for acute renal failure, though in the case of atorvastatin, the association was marginal, and furthermore, a signal was not detected for non-acute renal failure or for an increase in blood creatinine level. Data mining of the FDA's adverse event reporting system, AERS, is useful for examining statin-associated muscular and renal adverse events. The data strongly suggest the necessity of well-organized clinical studies with respect to statin-associated adverse events.
End-stage Renal Failure as a Complication of Acute Tubulo-Interstitial Nephritis

International Nuclear Information System (INIS)

Reda, G.; Ali, R.; Abdelrehman, M.; Sinha, A. K.; Ayman, K.

2005-01-01

Acute tubulo-interstitial nephritis (ATIN) is an important cause of acute renal failure, where renal impairement tends to be variable but recovery is the rule. End-stage renal failure (ESRF) has been rarely reported as a complication of ATIN. We report here a case of idiopathic ATIN that resulted in severe acute renal failure. The patient developed ESRF, which required permanent renal replacement therapy. (author)
Resolving epidemic network failures through differentiated repair times

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée; Manzano, Marc

2015-01-01

In this study, the authors investigate epidemic failure spreading in large-scale transport networks under generalisedmulti-protocol label switching control plane. By evaluating the effect of the epidemic failure spreading on the network,they design several strategies for cost-effective network pe...... assigninglower repair times among the network nodes. They believe that the event-driven simulation model can be highly beneficialfor network providers, since it could be used during the network planning process for facilitating cost-effective networksurvivability design.......In this study, the authors investigate epidemic failure spreading in large-scale transport networks under generalisedmulti-protocol label switching control plane. By evaluating the effect of the epidemic failure spreading on the network,they design several strategies for cost-effective network...... performance improvement via differentiated repair times. First, theyidentify the most vulnerable and the most strategic nodes in the network. Then, via extensive event-driven simulations theyshow that strategic placement of resources for improved failure recovery has better performance than randomly...
Memory-based detection of rare sound feature combinations in anesthetized rats.

Science.gov (United States)

Astikainen, Piia; Ruusuvirta, Timo; Wikgren, Jan; Penttonen, Markku

2006-10-02

It is unclear whether the ability of the brain to discriminate rare from frequently repeated combinations of sound features is limited to the normal sleep/wake cycle. We recorded epidural auditory event-related potentials in urethane-anesthetized rats presented with rare tones ('deviants') interspersed with frequently repeated ones ('standards'). Deviants differed from standards either in frequency alone or in frequency combined with intensity. In both cases, deviants elicited event-related potentials exceeding in amplitude event-related potentials to standards between 76 and 108 ms from the stimulus onset, suggesting the independence of the underlying integrative and memory-based change detection mechanisms of the brain from the normal sleep/wake cycle. The relations of these event-related potentials to mismatch negativity and N1 in humans are addressed.
A review for identification of initiating events in event tree development process on nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Riyadi, Eko H., E-mail: e.riyadi@bapeten.go.id [Center for Regulatory Assessment of Nuclear Installation and Materials, Nuclear Energy Regulatory Agency (BAPETEN), Jl. Gajah Mada 8 Jakarta 10120 (Indonesia)

2014-09-30

Initiating event is defined as any event either internal or external to the nuclear power plants (NPPs) that perturbs the steady state operation of the plant, if operating, thereby initiating an abnormal event such as transient or loss of coolant accident (LOCA) within the NPPs. These initiating events trigger sequences of events that challenge plant control and safety systems whose failure could potentially lead to core damage or large early release. Selection for initiating events consists of two steps i.e. first step, definition of possible events, such as by evaluating a comprehensive engineering, and by constructing a top level logic model. Then the second step, grouping of identified initiating event's by the safety function to be performed or combinations of systems responses. Therefore, the purpose of this paper is to discuss initiating events identification in event tree development process and to reviews other probabilistic safety assessments (PSA). The identification of initiating events also involves the past operating experience, review of other PSA, failure mode and effect analysis (FMEA), feedback from system modeling, and master logic diagram (special type of fault tree). By using the method of study for the condition of the traditional US PSA categorization in detail, could be obtained the important initiating events that are categorized into LOCA, transients and external events.
Modeling Temporal Processes in Early Spacecraft Design: Application of Discrete-Event Simulations for Darpa's F6 Program

Science.gov (United States)

Dubos, Gregory F.; Cornford, Steven

2012-01-01

While the ability to model the state of a space system over time is essential during spacecraft operations, the use of time-based simulations remains rare in preliminary design. The absence of the time dimension in most traditional early design tools can however become a hurdle when designing complex systems whose development and operations can be disrupted by various events, such as delays or failures. As the value delivered by a space system is highly affected by such events, exploring the trade space for designs that yield the maximum value calls for the explicit modeling of time.This paper discusses the use of discrete-event models to simulate spacecraft development schedule as well as operational scenarios and on-orbit resources in the presence of uncertainty. It illustrates how such simulations can be utilized to support trade studies, through the example of a tool developed for DARPA's F6 program to assist the design of "fractionated spacecraft".
Treatment of external events in the linked event tree methodology NPP Goesgen - Daeniken example

International Nuclear Information System (INIS)

Kozlik, Thomas

2014-01-01

The NPP Goesgen-Daeniken uses a combined level 1 / level 2 PSA model for its event analyses. The model uses a linked event tree approach, using the software RISKMAN R . Each initiating event passes through a modularized event tree structure, consisting of external events pre-trees, alignment and support systems trees and front-line and containment response trees. This paper explains the structure of the linked event trees. Switches are used to bypass certain trees for specific initiating events. The screening process applied to possible external events is explained. The final scope of considered natural external events in the Goesgen PSA consists of earthquakes, seasonal events causing cooling water intake plugging or external floods. The structure of the natural external events pre-trees is explained. The treatment of external floods is explained in more detail. Floods at the Goesgen site are caused by extreme river flows into the old branch of the Aare river. A new model has been developed to analyse the probabilistic flood hazard using a bivariate distribution (water level and flood duration). Analysing the statistical data, the time trend had to be considered. The Goesgen PSA models 7 external flood initiating events, considering different water levels and durations at the flooded plant site. The building fragilities were developed in terms of resistance times. The RISKMAN R external flood pre-tree consists of top events for operator actions and failure of the building functions, which leads to the functional failure of equipment located at the lower elevation of the building. (author)
Rooting out causes in failure analysis; Risk analysis

Energy Technology Data Exchange (ETDEWEB)

Keith, Graeme

2010-07-01

The Deepwater Horizon disaster was a terrible reminder of the consequences of equipment failure on facilities operating in challenging environments. Thankfully catastrophes on the scale of the Deepwater Horizon are rare, but equipment failure is a daily occurrence on installations around the globe. The consequences range from short unexpected downtime, to a total stop on production. from a brief burst of flaring to lasting environmental damage and from the momentary discomfiture of a worker to incapability or death. (Author)
A REVIEW OF SOFTWARE-INDUCED FAILURE EXPERIENCE.

Energy Technology Data Exchange (ETDEWEB)

CHU, T.L.; MARTINEZ-GURIDI, G.; YUE, M.; LEHNER, J.

2006-09-01

We present a review of software-induced failures in commercial nuclear power plants (NPPs) and in several non-nuclear industries. We discuss the approach used for connecting operational events related to these failures and the insights gained from this review. In particular, we elaborate on insights that can be used to model this kind of failure in a probabilistic risk assessment (PRA) model. We present the conclusions reached in these areas.
Galen's vein aneurysm as cause of heart failure

International Nuclear Information System (INIS)

Echeverria, Claudia; Cassalett, Gabriel; Franco, Jaime; Carrillo, Gustavo

2005-01-01

We present the case of a newborn admitted to the intensive care unit with a heart failure of difficult medical management. A large ductus arteriosus was found. It was surgically corrected, but the heart failure persisted and did not improve with medical treatment. Incidentally, a big Galen's vein aneurysm was found. Galen's vein aneurysm is a rare congenital pathology, originated by a fusion defect of the internal cerebral veins. Due to its low resistance, it produces a picture of high-output heart failure. Large defects may contain 50% to 60% of cardiac output. An aneurysm may be suspected in each newborn or infant with clinical picture of heart failure and right cardiac chamber dilation without any evidence of structural cardiac anomaly
Collections and Analyses of Common Cause Failure Data for the Korea Standard and Westinghouse Type NPPs

International Nuclear Information System (INIS)

Kang, Dae Il; Han, S. H.

2007-04-01

The analyses of the CCF events for domestic NPPs were performed to establish the domestic database for the CCF events and to deliver supply them to the operation office of the international common cause failure data exchange (ICDE) project. We collected and analyzed the CCF events of emergency diesel generators, centrifugal pumps, motor-operated valves, check valves, circuit breakers for the Korean Standard Type nuclear power plants (NPPs), Yonggwang Units 3 and 4 and Ulchin Units 3 and 4, and the Westinghouse type NPPs, Kori Unit 3 and 4 and Yonggwang Units 1 and 2. First, the components to be collected and analyzed were classified into the common cause component groups (CCCGs) according to the ICDE coding guidelines. Next, the CCF events were identified based on reviews of the component database for the PSA and its related documents, and consultations with NPP staff. Fourteen CCF events were identified. The ratio of the number of CCF events to that of individual failure events was identified as approximately 10 percentages. However, an in depth review of the CCF events showed that most failure severities of them were identified as partial CCF events, which can be interpreted as some component failures within the CCCGs. Root causes of the CCF events were identified as 9 internal part failures, 2 human errors, 2 design deficiencies, 1 procedure inadequacy. It could be concluded that the major root causes of the CCF events were internal piece part failures
Analysis of loss of offsite power events reported in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Volkanovski, Andrija, E-mail: Andrija.VOLKANOVSKI@ec.europa.eu [European Commission, Joint Research Centre, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Ballesteros Avila, Antonio; Peinador Veira, Miguel [European Commission, Joint Research Centre, Institute for Energy and Transport, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Kančev, Duško [Kernkraftwerk Goesgen-Daeniken AG, CH-4658 Daeniken (Switzerland); Maqua, Michael [Gesellschaft für Anlagen-und-Reaktorsicherheit (GRS) gGmbH, Schwertnergasse 1, 50667 Köln (Germany); Stephan, Jean-Luc [Institut de Radioprotection et de Sûreté Nucléaire (IRSN), BP 17 – 92262 Fontenay-aux-Roses Cedex (France)

2016-10-15

Highlights: • Loss of offsite power events were identified in four databases. • Engineering analysis of relevant events was done. • The dominant root cause for LOOP are human failures. • Improved maintenance procedures can decrease the number of LOOP events. - Abstract: This paper presents the results of analysis of the loss of offsite power events (LOOP) in four databases of operational events. The screened databases include: the Gesellschaft für Anlagen und Reaktorsicherheit mbH (GRS) and Institut de Radioprotection et de Sûreté Nucléaire (IRSN) databases, the IAEA International Reporting System for Operating Experience (IRS) and the U.S. Licensee Event Reports (LER). In total 228 relevant loss of offsite power events were identified in the IRSN database, 190 in the GRS database, 120 in U.S. LER and 52 in IRS database. Identified events were classified in predefined categories. Obtained results show that the largest percentage of LOOP events is registered during On power operational mode and lasted for two minutes or more. The plant centered events is the main contributor to LOOP events identified in IRSN, GRS and IAEA IRS database. The switchyard centered events are the main contributor in events registered in the NRC LER database. The main type of failed equipment is switchyard failures in IRSN and IAEA IRS, main or secondary lines in NRC LER and busbar failures in GRS database. The dominant root cause for the LOOP events are human failures during test, inspection and maintenance followed by human failures due to the insufficient or wrong procedures. The largest number of LOOP events resulted in reactor trip followed by EDG start. The actions that can result in reduction of the number of LOOP events and minimize consequences on plant safety are identified and presented.
Simulation of the 23 July 2012 Extreme Space Weather Event: What if This Extremely Rare CME Was Earth Directed?

Science.gov (United States)

Ngwira, Chigomezyo M.; Pulkkinen, Antti; Mays, M. Leila; Kuznetsova, Maria M.; Galvin, A. B.; Simunac, Kristin; Baker, Daniel N.; Li, Xinlin; Zheng, Yihua; Glocer, Alex

2013-01-01

Extreme space weather events are known to cause adverse impacts on critical modern day technological infrastructure such as high-voltage electric power transmission grids. On 23 July 2012, NASA's Solar Terrestrial Relations Observatory-Ahead (STEREO-A) spacecraft observed in situ an extremely fast coronal mass ejection (CME) that traveled 0.96 astronomical units (approx. 1 AU) in about 19 h. Here we use the SpaceWeather Modeling Framework (SWMF) to perform a simulation of this rare CME.We consider STEREO-A in situ observations to represent the upstream L1 solar wind boundary conditions. The goal of this study is to examine what would have happened if this Rare-type CME was Earth-bound. Global SWMF-generated ground geomagnetic field perturbations are used to compute the simulated induced geoelectric field at specific ground-based active INTERMAGNET magnetometer sites. Simulation results show that while modeled global SYM-H index, a high-resolution equivalent of the Dst index, was comparable to previously observed severe geomagnetic storms such as the Halloween 2003 storm, the 23 July CME would have produced some of the largest geomagnetically induced electric fields, making it very geoeffective. These results have important practical applications for risk management of electrical power grids.
Serious adverse events with infliximab: analysis of spontaneously reported adverse events.

Science.gov (United States)

Hansen, Richard A; Gartlehner, Gerald; Powell, Gregory E; Sandler, Robert S

2007-06-01

Serious adverse events such as bowel obstruction, heart failure, infection, lymphoma, and neuropathy have been reported with infliximab. The aims of this study were to explore adverse event signals with infliximab by using a long period of post-marketing experience, stratifying by indication. The relative reporting of infliximab adverse events to the U.S. Food and Drug Administration (FDA) was assessed with the public release version of the adverse event reporting system (AERS) database from 1968 to third quarter 2005. On the basis of a systematic review of adverse events, Medical Dictionary for Regulatory Activities (MedDRA) terms were mapped to predefined categories of adverse events, including death, heart failure, hepatitis, infection, infusion reaction, lymphoma, myelosuppression, neuropathy, and obstruction. Disproportionality analysis was used to calculate the empiric Bayes geometric mean (EBGM) and corresponding 90% confidence intervals (EB05, EB95) for adverse event categories. Infliximab was identified as the suspect medication in 18,220 reports in the FDA AERS database. We identified a signal for lymphoma (EB05 = 6.9), neuropathy (EB05 = 3.8), infection (EB05 = 2.9), and bowel obstruction (EB05 = 2.8). The signal for granulomatous infections was stronger than the signal for non-granulomatous infections (EB05 = 12.6 and 2.4, respectively). The signals for bowel obstruction and infusion reaction were specific to patients with IBD; this suggests potential confounding by indication, especially for bowel obstruction. In light of this additional evidence of risk of lymphoma, neuropathy, and granulomatous infections, clinicians should stress this risk in the shared decision-making process.

Post-radiational ureteric fibrosis with extrarenal renal failure as a rare complication after adjuvant treatment of gastric cancer - a case report

International Nuclear Information System (INIS)

Swieboda-Sadlej, A.; Staszewska-Skurczynska, M.; Piyush Vyas; Zurawinska, E.; Heleniak, H.; Kocik, J.; Danek, A.; Tragarz, E.

2008-01-01

The principles of chemoradiotherapy for treating patients with radically resected gastric cancer are not fully established. In many oncological centres patients with unfavourable prognostic factors who previously had radical gastrectomy are treated with Macdonald regimen which includes combined fluorouracil with radiotherapy. Statistics indicate that more then 30% patients treated with chemoradiotherapy suffer from serious complication. In this article we describe a case of a patient who developed ureteric fibrosis with consequent renal failure as a rare life threatening complication of Macdonald regimen. The patient received chemoradiotherapy because of unfavourable prognostic factors and good performance status however he was in advanced age and with other comorbidities. These data support the notion of the high toxicity of this regimen and suggest that selection of patients for this treatment should be done very carefully. This is discussed in the context of other available therapies in gastric cancer. (author)
Regulatory experience with fuel failures in Switzerland

International Nuclear Information System (INIS)

Adam, L.

2015-01-01

In this paper the main ENSI activities like: supervision of reactor and radiation safety and security; supervision of safety of transports of nuclear materials and assess the safety of proposed solutions for the geological disposal are listed. Recent events concerning the reactor core, common causes for fuel failures, findings during inspections and potential root cause for fuel failures are discussed. Management of fuel failures, started from reporting of the event – evaluation of the need of imminent action; identification of the fuel element if possible till evaluation by the plant and fuel vendor and allowance by ENSI for repair of the fuel element and definition of measures (short and long term) are also presented. The following Conclusions by ENSI about status of fuel failures are made: 1) Number of fuel failures was reduced regardless more economic operation in all plants; 2) Old PWR and BWR reactors achieved 15 to 29 years operation without leakers, but two minor fuel damage during fuel handling appeared; 3) Newer plants are not better in achieving operation without leakers than older plants; 4) Technical improvements at fuel elements parallel to changes in operation strategy and improvements in manufacturing quality but single effects difficult to judge. The issues about how to implement “Zero Failure Rates” in regulations and how to achieve “Zero Failure Rates” as well as some future measures by ENSI are discussed
Seismic ratchet-fatigue failure of piping systems

International Nuclear Information System (INIS)

Severud, L.K.; Anderson, M.J.; Lindquist, M.R.; Weiner, E.O.

1986-01-01

Failures of piping systems during earthquakes have been rare. Those that have failed were either made of brittle material such as cast iron, were rigid systems between major components where component relative seismic motions tore the pipe out of the component, or were high pressure systems where a ratchet-fatigue fracture followed a local bulging of the pipe diameter. Tests to failure of an unpressurized 3-in. and a pressurized 6-in. diameter carbon steel nuclear pipe systems subjected to high level shaking have been accomplished. Failure analyses of these tests are presented and correlated to the test results. It was found that failure of the unpressurized system could be correlated well with standard ASME type fatigue analysis predictions. Moreover, the pressurized system failure occurred in significantly less load cycles than predicted by standard fatigue analysis. However, a ratchet-fatigue and ductility exhaustion analysis of the pressurized system did correlate very well. These findings indicate modifications to design analysis methods and the present ASME Code piping design rules may be appropriate to cover the ratchet-fatigue failure mode
A Study of the Impact of Peak Demand on Increasing Vulnerability of Cascading Failures to Extreme Contingency Events

Energy Technology Data Exchange (ETDEWEB)

Vyakaranam, Bharat GNVSR; Vallem, Mallikarjuna R.; Nguyen, Tony B.; Samaan, Nader A.; Berscheid, Alan P.; Makarov, Yuri V.; Diao, Ruisheng

2017-10-02

The vulnerability of large power systems to cascading failures and major blackouts has become evident since the Northeast blackout in 1965. Based on analyses of the series of cascading blackouts in the past decade, the research community realized the urgent need to develop better methods, tools, and practices for performing cascading-outage analysis and for evaluating mitigations that are easily accessible by utility planning engineers. PNNL has developed the Dynamic Contingency Analysis Tool (DCAT) as an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. DCAT analysis will help identify potential vulnerabilities and allow study of mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. Using the DCAT capability, we examined the impacts of various load conditions to identify situations in which the power grid may encounter cascading outages that could lead to potential blackouts. This paper describes the usefulness of the DCAT tool and how it helps to understand potential impacts of load demand on cascading failures on the power system.
Patterns of failure following treatment for medulloblastoma: is it necessary to treat the entire posterior fossa?

International Nuclear Information System (INIS)

Fukunaga-Johnson, Nina; Lee, Jason H.; Robertson, Patricia; Sandler, Howard M.; McNeil, Elizabeth; Goldwein, Joel W.

1997-01-01

as the solitary site of first failure in only (1(27)) failures. (11(14)) patients who failed in the tumor bed also failed in the spine, (8(14)) also failed within the PF but outside the tumor bed, and (7(14)) failed in the all three locations. Local failure within the PF but outside the tumor bed as any component of first failure occurred in 41% ((11(27))) of all failures but as the solitary site of first failure in only (1(27)) failures. Nine of 11 patients who failed in the PF but outside the tumor bed also failed in the spine, (8(11)) also failed within the tumor bed, and (7(11)) failed in the all three locations. Of the failures outside the tumor bed but still within the PF, (7(11)) failed in the leptomeninges, (1(11)) in the brainstem parenchyma, and (3(11)) in the PF parenchyma. (6(7)) who failed in the PF leptomeninges also failed within the spine. Failure within the spine as any component of first failure occurred in 70% ((19(27))) of all failures and as the only site of first failure in (5(27)) patients. (11(19)) patients who failed in the spine also failed in the tumor bed, (9(19)) also failed within the PF but outside the tumor bed, and (9(19)) failed in the all three locations. Conclusions: Leptomeningeal failure is a common component of failure and occurs in the leptomeninges of the PF as well as the spine. Isolated tumor bed failure is a rarely observed event and occurred in only (1(27)) failures here described. Similarly, parenchymal (non-leptomengingeal) failures in the PF but outside of the tumor bed were rare: 4 patients recurred in this manner, only 1 of which was an isolated event without other sites of recurrence. These data suggest that when the entire PF is treated, very few failures develop in the PF outside the tumor bed. Further studies will be necessary to determine whether RT the tumor bed alone will suffice as opposed to a boost to the entire PF. The former approach using 3D conformal therapy may minimize the ototoxicity and other
[Pseudohypoaldosteronisme type I: a rare cause of failure to thrive].

Science.gov (United States)

Derache, A-F; Rousseau, S; Holder-Espinasse, M; Bouquillon, S; Bresson, S; Ythier, H; Ganga-Zandzou, P-S

2012-05-01

We report on a boy, born on term, presenting with a weight loss and a persistent failure to thrive after 10 days despite a normal behavior under bottle-feeding. The clinical examination was normal and biological assessment revealed hyponatremia with hyponatriuria, normal kaliemia and elevated aldosterone values, leading to type I pseudohypoaldosteronism diagnosis. Treatment with salt supplementation allowed growth improvement. The diagnosis was confirmed by the identification of a mutation in the mineralocorticoid receptor. This change was also found in several family members. Copyright © 2012 Elsevier Masson SAS. All rights reserved.
Canada - Atomic Energy Control Board, Canada. Summary of a common cause failure event which occurred in a Canadian utility. 'Failure to Verify Poison Isotopic'

International Nuclear Information System (INIS)

1996-01-01

Operating Policies and Principles (OP and Ps) are referenced in the reactor operating license. They contain not only general safety principles, but also define safety parameters and their numerical values for the operation of the nuclear power plant. The event described highlights the difficulties to implement the OP and Ps into detailed purchase orders. In Candu reactors gadolinium nitrate and boric oxide are used as neutron absorbers in the moderator. The concentration of neutron absorbers in the moderator is safety significant because a small change in concentration in coincidence with other failures (e.g. LOCA) can result in a sudden increase of power. To ensure that new shipments of gadolinium nitrate or boric acid meet the required specifications, these must undergo quarantine so that samples could be taken and forwarded for analysis. The chemistry unit of the NPP issued this requirements in a 'note to file'. In the event, two separated purchase orders, one for gadolinium nitrate and one for boric oxide, were placed. The purchase orders did not stipulate the requirements to quarantine, inform the chemistry unit or to analyse samples. They only stated that correct isotopic and chemical purity were required. The gadolinium nitrate as well as the boron oxide were both not quarantined and even the purity was not verified. The chemistry unit felt that a 'note to file' memo was sufficient to ensure that the OP and Ps are met taking into account the low shipment rate and sufficient experiences before. The analysis of the event revealed several causal factors. Four main factors were pointed out: - Work practices, - Resource Management, - Written communication, - Managerial methods. The actions taken after the event focused on the identified deficiencies
Failure Waves in Cylindrical Glass Bars

Science.gov (United States)

Cazamias, James U.; Bless, Stephan J.; Marder, Michael P.

1997-07-01

Failure waves, a propagating front separating virgin and comminuted material, have been receiving a fair amount of attention the last couple of years. While most scientists have been looking at failure waves in plate impact geometries, we have conducted a series of experiments on Pyrex bars. In this paper, we present two types of photographic data from a series of tests. A streak camera was used to determine velocities of the failure front as a function of impact stress. A polaroid camera and a flash lamp provide detailed pictures of the actual event. Attempts were made to observe failure waves in amorphous quartz and acrylic.
Ingested razor blades within the appendix: A rare case report

Directory of Open Access Journals (Sweden)

Jason Cui

Full Text Available Introduction: Foreign body ingestion is a common clinical presentation with less than 1% of the cases requiring surgical intervention. In this report, we present a rare case of razor blades lodged in the appendix as a result of intentional ingestion. Presentation of case: A 25 year old male prisoner presented to our hospital with persistent right iliac fossa pain after razor blade ingestion. After 5 days of conservative management, there was no sign of transition on serial X-Rays. Laparoscopy with intraoperative image intensification confirmed the presence of the razor blades in the appendix and appendicectomy was subsequently performed without complications. Discussion: Most ingested objected with diameter less than 2.5 cm and length less than 6 cm can pass through the gastrointestinal tract spontaneously in less than one week. The entry of foreign objects into the appendix is thought to be due to relative low motility of the caecum, the dependent position of the appendix and the size of the appendiceal orifice. Radiographic localisation to the appendiceal lumen was complicated by metallic artefact, but was consistent with failure to transit. Appendicectomy was felt to be the safest mode of retrieval. Conclusion: Ingested foreign body lodged in the appendix is a rare event. Once the exact location is confirmed, a simple laparoscopic appendicectomy can be performed to facilitate the removal. Keywords: Appendicitis, Laparoscopy, Appendicectomy, Foreign body ingestion, Razor blades, Case report
Probabilistic analysis on the failure of reactivity control for the PWR

Science.gov (United States)

Sony Tjahyani, D. T.; Deswandri; Sunaryo, G. R.

2018-02-01

The fundamental safety function of the power reactor is to control reactivity, to remove heat from the reactor, and to confine radioactive material. The safety analysis is used to ensure that each parameter is fulfilled during the design and is done by deterministic and probabilistic method. The analysis of reactivity control is important to be done because it will affect the other of fundamental safety functions. The purpose of this research is to determine the failure probability of the reactivity control and its failure contribution on a PWR design. The analysis is carried out by determining intermediate events, which cause the failure of reactivity control. Furthermore, the basic event is determined by deductive method using the fault tree analysis. The AP1000 is used as the object of research. The probability data of component failure or human error, which is used in the analysis, is collected from IAEA, Westinghouse, NRC and other published documents. The results show that there are six intermediate events, which can cause the failure of the reactivity control. These intermediate events are uncontrolled rod bank withdrawal at low power or full power, malfunction of boron dilution, misalignment of control rod withdrawal, malfunction of improper position of fuel assembly and ejection of control rod. The failure probability of reactivity control is 1.49E-03 per year. The causes of failures which are affected by human factor are boron dilution, misalignment of control rod withdrawal and malfunction of improper position for fuel assembly. Based on the assessment, it is concluded that the failure probability of reactivity control on the PWR is still within the IAEA criteria.
Evolution caused by extreme events.

Science.gov (United States)

Grant, Peter R; Grant, B Rosemary; Huey, Raymond B; Johnson, Marc T J; Knoll, Andrew H; Schmitt, Johanna

2017-06-19

Extreme events can be a major driver of evolutionary change over geological and contemporary timescales. Outstanding examples are evolutionary diversification following mass extinctions caused by extreme volcanism or asteroid impact. The evolution of organisms in contemporary time is typically viewed as a gradual and incremental process that results from genetic change, environmental perturbation or both. However, contemporary environments occasionally experience strong perturbations such as heat waves, floods, hurricanes, droughts and pest outbreaks. These extreme events set up strong selection pressures on organisms, and are small-scale analogues of the dramatic changes documented in the fossil record. Because extreme events are rare, almost by definition, they are difficult to study. So far most attention has been given to their ecological rather than to their evolutionary consequences. We review several case studies of contemporary evolution in response to two types of extreme environmental perturbations, episodic (pulse) or prolonged (press). Evolution is most likely to occur when extreme events alter community composition. We encourage investigators to be prepared for evolutionary change in response to rare events during long-term field studies.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).
Computer-assisted imaging algorithms facilitate histomorphometric quantification of kidney damage in rodent renal failure models

Directory of Open Access Journals (Sweden)

Marcin Klapczynski

2012-01-01

Full Text Available Introduction: Surgical 5/6 nephrectomy and adenine-induced kidney failure in rats are frequently used models of progressive renal failure. In both models, rats develop significant morphological changes in the kidneys and quantification of these changes can be used to measure the efficacy of prophylactic or therapeutic approaches. In this study, the Aperio Genie Pattern Recognition technology, along with the Positive Pixel Count, Nuclear and Rare Event algorithms were used to quantify histological changes in both rat renal failure models. Methods: Analysis was performed on digitized slides of whole kidney sagittal sections stained with either hematoxylin and eosin or immunohistochemistry with an anti-nestin antibody to identify glomeruli, regenerating tubular epithelium, and tubulointerstitial myofibroblasts. An anti-polymorphonuclear neutrophil (PMN antibody was also used to investigate neutrophil tissue infiltration. Results: Image analysis allowed for rapid and accurate quantification of relevant histopathologic changes such as increased cellularity and expansion of glomeruli, renal tubular dilatation, and degeneration, tissue inflammation, and mineral aggregation. The algorithms provided reliable and consistent results in both control and experimental groups and presented a quantifiable degree of damage associated with each model. Conclusion: These algorithms represent useful tools for the uniform and reproducible characterization of common histomorphologic features of renal injury in rats.
ξ common cause failure model and method for defense effectiveness estimation

International Nuclear Information System (INIS)

Li Zhaohuan

1991-08-01

Two issues have been dealt. One is to develop an event based parametric model called ξ-CCF model. Its parameters are expressed in the fraction of the progressive multiplicities of failure events. By these expressions, the contribution of each multiple failure can be presented more clearly. It can help to select defense tactics against common cause failures. The other is to provide a method which is based on the operational experience and engineering judgement to estimate the effectiveness of defense tactics. It is expressed in terms of reduction matrix for a given tactics on a specific plant in the event by event form. The application of practical example shows that the model in cooperation with the method can simply estimate the effectiveness of defense tactics. It can be easily used by the operators and its application may be extended
A replica exchange transition interface sampling method with multiple interface sets for investigating networks of rare events

Science.gov (United States)

Swenson, David W. H.; Bolhuis, Peter G.

2014-07-01

The multiple state transition interface sampling (TIS) framework in principle allows the simulation of a large network of complex rare event transitions, but in practice suffers from convergence problems. To improve convergence, we combine multiple state TIS [J. Rogal and P. G. Bolhuis, J. Chem. Phys. 129, 224107 (2008)] with replica exchange TIS [T. S. van Erp, Phys. Rev. Lett. 98, 268301 (2007)]. In addition, we introduce multiple interface sets, which allow more than one order parameter to be defined for each state. We illustrate the methodology on a model system of multiple independent dimers, each with two states. For reaction networks with up to 64 microstates, we determine the kinetics in the microcanonical ensemble, and discuss the convergence properties of the sampling scheme. For this model, we find that the kinetics depend on the instantaneous composition of the system. We explain this dependence in terms of the system's potential and kinetic energy.
Black-swan events in animal populations

OpenAIRE

Anderson, Sean C.; Branch, Trevor A.; Cooper, Andrew B.; Dulvy, Nicholas K.

2017-01-01

Black swans?statistically improbable events with profound consequences?happen more often than expected in financial, social, and natural systems. Our work demonstrates the rare but systematic presence of black-swan events in animal populations around the world (mostly birds, mammals, and insects). These events are predominantly downward, implying that unexpected population crashes occur more frequently than increases. Black-swan events are not driven by life history (e.g., lifespan) but by ex...
Is human failure a stochastic process?

International Nuclear Information System (INIS)

Dougherty, Ed M.

1997-01-01

Human performance results in failure events that occur with a risk-significant frequency. System analysts have taken for granted the random (stochastic) nature of these events in engineering assessments such as risk assessment. However, cognitive scientists and error technologists, at least those who have interest in human reliability, have, over the recent years, claimed that human error does not need this stochastic framework. Yet they still use the language appropriate to stochastic processes. This paper examines the potential for the stochastic nature of human failure production as the basis for human reliability analysis. It distinguishes and leaves to others, however, the epistemic uncertainties over the possible probability models for the real variability of human performance
Determination of Component Failure Modes for a Fire PSA by Using Decision Trees

International Nuclear Information System (INIS)

Kang, Dae Il; Han, Sang Hoon; Lim, Jae Won

2007-01-01

KAERI developed the method, called a mapping technique, for the quantification of external events PSA models with one top model for an internal events PSA. The mapping technique can be implemented by the construction of mapping tables. The mapping tables include initiating events and transfer events of fire, and internal PSA basic events affected by a fire. This year, KAERI is making mapping tables for the one top model for Ulchin Unit 3 and 4 fire PSA with previously conducted Fire PSA results for Ulchin Unit 3 and 4. A Fire PSA requires a PSA analyst to determine component failure modes affected by a fire. The component failure modes caused by a fire depend on several factors. These several factors are whether components are located at fire initiation and propagation areas or not, fire effects on control and power cables for components, designed failure modes of components, success criteria in a PSA model, etc. Thus, it is not easy to manually determine component failure modes caused by a fire. In this paper, we propose the use of decision trees for the determination of component failure modes affected by a fire and the selection of internal PSA basic events. Section 2 presents the procedure for previously performed the Ulchin Unit 3 and 4 fire PSA and mapping technique. Section 3 presents the process for identification of basic events and decision trees. Section 4 presents the concluding remarks
Rare adverse events associated with oral poliovirus vaccine in Brazil

Directory of Open Access Journals (Sweden)

Friedrich F.

1997-01-01

Full Text Available Oral poliovirus vaccine (OPV developed by A. Sabin has been effectively used to control poliomyelitis in Brazil, and the last case with the isolation of a wild poliovirus strain occurred in March 1989. Although the vaccine controlled the circulation of wild strains and poliomyelitis cases associated with these strains were not detected during the last eight years, rare cases classified as vaccine-associated paralytic poliomyelitis (VAPP have been detected. Molecular characterization studies of poliovirus strains isolated from VAPP cases and from healthy contacts have confirmed that the isolates are derived from the Sabin vaccine strains and also detected genomic modifications known or suspected to increase neurovirulence such as mutations and recombination. The molecular characterization of polioviruses isolated during the last eight years from paralysis cases classified as Guillain-Barré (GBS syndrome and transverse myelitits (TM, and from facial paralysis (FP cases also confirmed the vaccine origin of the strains and demonstrated mutations known to increase neurovirulence. Analysis of the epidemiologic data of these GBS, TM and FP cases demonstrated that in most of them the last OPV dose was given months or years before the onset of the disease and the isolation of the polioviruses. The temporal association between the isolation of these strains and the GBS, TM and FP suggested that the Sabin vaccine-derived poliovirus strains could also rarely trigger the diseases.
Failure to thrive: an update.

Science.gov (United States)

Cole, Sarah Z; Lanham, Jason S

2011-04-01

Failure to thrive in childhood is a state of undernutrition due to inadequate caloric intake, inadequate caloric absorption, or excessive caloric expenditure. In the United States, it is seen in 5 to 10 percent of children in primary care settings. Although failure to thrive is often defined as a weight for age that falls below the 5th percentile on multiple occasions or weight deceleration that crosses two major percentile lines on a growth chart, use of any single indicator has a low positive predictive value. Most cases of failure to thrive involve inadequate caloric intake caused by behavioral or psychosocial issues. The most important part of the outpatient evaluation is obtaining an accurate account of a child's eating habits and caloric intake. Routine laboratory testing rarely identifies a cause and is not generally recommended. Reasons to hospitalize a child for further evaluation include failure of outpatient management, suspicion of abuse or neglect, or severe psychosocial impairment of the caregiver. A multidisciplinary approach to treatment, including home nursing visits and nutritional counseling, has been shown to improve weight gain, parent-child relationships, and cognitive development. The long-term effects of failure to thrive on cognitive development and future academic performance are unclear.
The application of Petri nets to failure analysis

International Nuclear Information System (INIS)

Liu, T.S.; Chiou, S.B.

1997-01-01

Unlike the technique of fault tree analysis that has been widely applied to system failure analysis in reliability engineering, this study presents a Petri net approach to failure analysis. It is essentially a graphical method for describing relations between conditions and events. The use of Petri nets in failure analysis enables to replace logic gate functions in fault trees, efficiently obtain minimal cut sets, and absorb models. It is demonstrated that for failure analysis Petri nets are more efficient than fault trees. In addition, this study devises an alternative; namely, a trapezoidal graph method in order to account for failure scenarios. Examples validate this novel method in dealing with failure analysis

A study of common-mode failures

International Nuclear Information System (INIS)

Edwards, G.T.; Watson, I.A.

1979-07-01

The purpose of the report is to investigate problems of the identification of the common failure mode (CFM) the reliability models used and the data required for their solution, particularly with regard to automatic protection systems for nuclear reactors. The available literature which was surveyed during the study is quoted and used as a basis for the main work of the study. The type of redundancy system under consideration is initially described and the types of CFM to which these systems are prone are identified before a general definition of the term 'common mode failure' is proposed. The definition and proposed classification system for CMF are based on the common cause of failure, so identifying the primary events. Defences against CFM are included and proposals for an overall strategy and detailed recommendations for design and operation are made. Common mode failures in US nuclear reactor systems, aircraft systems, and other sources including chemical plant systems are surveyed. The data indicates the importance of the human error problem in the causes of CMF in design, maintenance and operation. From a study of the collected data a redundancy sub-system model for CMF is developed which identifies three main categories of failure, non-recurrent engineering design errors, maintenance and test errors, and random interest events. The model proposed allows for the improvement in sub-system reliability where appropriate defences are applied. (author)
The five-point Likert scale for dyspnea can properly assess the degree of pulmonary congestion and predict adverse events in heart failure outpatients

Directory of Open Access Journals (Sweden)

Cristina K. Weber

2014-01-01

Full Text Available OBJECTIVES: Proper assessment of dyspnea is important in patients with heart failure. Our aim was to evaluate the use of the 5-point Likert scale for dyspnea to assess the degree of pulmonary congestion and to determine the prognostic value of this scale for predicting adverse events in heart failure outpatients. METHODS: We undertook a prospective study of outpatients with moderate to severe heart failure. The 5-point Likert scale was applied during regular outpatient visits, along with clinical assessments. Lung ultrasound with ≥15 B-lines and an amino-terminal portion of pro-B-type natriuretic peptide (NT-proBNP level >1000 pg/mL were used as a reference for pulmonary congestion. The patients were then assessed every 30 days during follow-up to identify adverse clinical outcomes. RESULTS: We included 58 patients (65.5% male, age 43.5±11 years with a mean left ventricular ejection fraction of 27±6%. In total, 29.3% of these patients had heart failure with ischemic etiology. Additionally, pulmonary congestion, as diagnosed by lung ultrasound, was present in 58% of patients. A higher degree of dyspnea (3 or 4 points on the 5-point Likert scale was significantly correlated with a higher number of B-lines (p = 0.016. Patients stratified into Likert = 3-4 were at increased risk of admission compared with those in class 1-2 after adjusting for age, left ventricular ejection fraction, New York Heart Association functional class and levels of NT-proBNP >1000 pg/mL (HR = 4.9, 95% CI 1.33-18.64, p = 0.017. CONCLUSION: In our series, higher baseline scores on the 5-point Likert scale were related to pulmonary congestion and were independently associated with adverse events during follow-up. This simple clinical tool can help to identify patients who are more likely to decompensate and whose treatment should be intensified.
Anticoagulant therapy and outcomes in patients with prior or acute heart failure and acute coronary syndromes: Insights from the APixaban for PRevention of Acute ISchemic Events 2 trial.

Science.gov (United States)

Cornel, Jan H; Lopes, Renato D; James, Stefan; Stevens, Susanna R; Neely, Megan L; Liaw, Danny; Miller, Julie; Mohan, Puneet; Amerena, John; Raev, Dimitar; Huo, Yong; Urina-Triana, Miguel; Gallegos Cazorla, Alex; Vinereanu, Dragos; Fridrich, Viliam; Harrington, Robert A; Wallentin, Lars; Alexander, John H

2015-04-01

Clinical outcomes and the effects of oral anticoagulants among patients with acute coronary syndrome (ACS) and either a history of or acute heart failure (HF) are largely unknown. We aimed to assess the relationship between prior HF or acute HF complicating an index ACS event and subsequent clinical outcomes and the efficacy and safety of apixaban compared with placebo in these populations. High-risk patients were randomly assigned post-ACS to apixaban 5.0 mg or placebo twice daily. Median follow-up was 8 (4-12) months. The primary outcome was cardiovascular death, myocardial infarction, or stroke. The main safety outcome was thrombolysis in myocardial infarction major bleeding. Heart failure was reported in 2,995 patients (41%), either as prior HF (2,076 [28%]) or acute HF (2,028 [27%]). Patients with HF had a very high baseline risk and were more often managed medically. Heart failure was associated with a higher rate of the primary outcome (prior HF: adjusted hazard ratio [HR] 1.73, 95% CI 1.42-2.10, P acute HF: adjusted HR 1.65, 95% CI 1.35-2.01, P acute HF: adjusted HR 2.52, 95% CI 1.82-3.50). Patients with acute HF also had significantly higher rates of thrombolysis in myocardial infarction major bleeding (prior HF: adjusted HR 1.22, 95% CI 0.65-2.27, P = .54, acute HF: adjusted HR 1.78, 95% CI 1.03-3.08, P = .04). There was no statistical evidence of a differential effect of apixaban on clinical events or bleeding in patients with or without prior HF; however, among patients with acute HF, there were numerically fewer events with apixaban than placebo (14.8 vs 19.3, HR 0.76, 95% CI 0.57-1.01, interaction P = .13), a trend that was not seen in patients with prior HF or no HF. In high-risk patients post-ACS, both prior and acute HFs are associated with an increased risk of subsequent clinical events. Apixaban did not significantly reduce clinical events and increased bleeding in patients with and without HF; however, there was a tendency toward fewer clinical
Economic impact of heart failure according to the effects of kidney failure.

Science.gov (United States)

Sicras Mainar, Antoni; Navarro Artieda, Ruth; Ibáñez Nolla, Jordi

2015-01-01

To evaluate the use of health care resources and their cost according to the effects of kidney failure in heart failure patients during 2-year follow-up in a population setting. Observational retrospective study based on a review of medical records. The study included patients ≥ 45 years treated for heart failure from 2008 to 2010. The patients were divided into 2 groups according to the presence/absence of KF. Main outcome variables were comorbidity, clinical status (functional class, etiology), metabolic syndrome, costs, and new cases of cardiovascular events and kidney failure. The cost model included direct and indirect health care costs. Statistical analysis included multiple regression models. The study recruited 1600 patients (prevalence, 4.0%; mean age 72.4 years; women, 59.7%). Of these patients, 70.1% had hypertension, 47.1% had dyslipidemia, and 36.2% had diabetes mellitus. We analyzed 433 patients (27.1%) with kidney failure and 1167 (72.9%) without kidney failure. Patients with kidney failure were associated with functional class III-IV (54.1% vs 40.8%) and metabolic syndrome (65.3% vs 51.9%, P<.01). The average unit cost was €10,711.40. The corrected cost in the presence of kidney failure was €14,868.20 vs €9,364.50 (P=.001). During follow-up, 11.7% patients developed ischemic heart disease, 18.8% developed kidney failure, and 36.1% developed heart failure exacerbation. Comorbidity associated with heart failure is high. The presence of kidney failure increases the use of health resources and leads to higher costs within the National Health System. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.
Albania’s Transformation since 1997: Successes and Failures

Directory of Open Access Journals (Sweden)

Jusufi Islam

2017-03-01

Full Text Available In 1997 Albania experienced a collapse of order and widespread violence, which resulted in a situation where the government was overthrown and some 2,000 people were killed. The 1997 disorder came as a result of the collapse of fraudulent financial pyramid schemes that had all the features of a war-like economic structure. During the 1997 events, large-scale confiscation and stealing of state assets occurred. Albania’s transitional period from communism to democracy, which began in 1990, led to the establishment of new structures for profiting from the country’s resources. Some of these political and economic structures, in the aftermath of the 1997 events, disappeared and others, including their structural effects, persist and have had an impact on the country’s political stability and economic progress. Today, both the successes and failures of the country are assessed based on the progress that the country has made since the 1997 events. The paper analyses the 1997 events and the transformation of Albania’s political and economic structures between 1997 and 2016, considering both achievements and failures. It looks at how the country has dealt with the post-1997 peace-building and development agenda from the perspective of it being a success. It looks at the factors that led to state failure in 1997 and at the factors that continue and have generated a path dependency to the current political context of the country. Although a lot has been written concerning the 1997 events, very little analysis has been conducted concerning what it means from the perspective of research on state failure. In this context, the proposed paper seeks to offer Albania as a case study example of a transformation process, from the uprising to the current situation, which is characterized as a mixture of successes and failures. The belief is that the proposed paper will point to some lessons learned for the strategies directed at the transformation processes.
Spacecraft electrical power subsystem: Failure behavior, reliability, and multi-state failure analyses

International Nuclear Information System (INIS)

Kim, So Young; Castet, Jean-Francois; Saleh, Joseph H.

2012-01-01

This article investigates the degradation and failure behavior of spacecraft electrical power subsystem (EPS) on orbit. First, this work provides updated statistical reliability and multi-state failure analyses of spacecraft EPS and its different constituents, namely the batteries, the power distribution, and the solar arrays. The EPS is shown to suffer from infant mortality and to be a major driver of spacecraft unreliability. Over 25% of all spacecraft failures are the result of EPS failures. As a result, satellite manufacturers may wish to pursue targeted improvement to this subsystem, either through better testing or burn-in procedures, better design or parts selection, or additional redundancy. Second, this work investigates potential differences in the EPS degradation and failure behavior for spacecraft in low earth orbits (LEO) and geosynchronous orbits (GEO). This analysis was motivated by the recognition that the power/load cycles and the space environment are significantly different in LEO and GEO, and as such, they may result in different failure behavior for the EPS in these two types of orbits. The results indicate, and quantify the extent to which, the EPS fails differently in LEO and GEO, both in terms of frequency and severity of failure events. A casual summary of the findings can be stated as follows: the EPS fails less frequently but harder (with fatal consequences to the spacecraft) in LEO than in GEO.
Reliability-based failure cause assessment of collapsed bridge during construction

International Nuclear Information System (INIS)

Choi, Hyun-Ho; Lee, Sang-Yoon; Choi, Il-Yoon; Cho, Hyo-Nam; Mahadevan, Sankaran

2006-01-01

Until now, in many forensic reports, the failure cause assessments are usually carried out by a deterministic approach so far. However, it may be possible for the forensic investigation to lead to unreasonable results far from the real collapse scenario, because the deterministic approach does not systematically take into account any information on the uncertainties involved in the failures of structures. Reliability-based failure cause assessment (reliability-based forensic engineering) methodology is developed which can incorporate the uncertainties involved in structural failures and structures, and to apply them to the collapsed bridge in order to identify the most critical failure scenario and find the cause that triggered the bridge collapse. Moreover, to save the time and cost of evaluation, an algorithm of automated event tree analysis (ETA) is proposed and possible to automatically calculate the failure probabilities of the failure events and the occurrence probabilities of failure scenarios. Also, for reliability analysis, uncertainties are estimated more reasonably by using the Bayesian approach based on the experimental laboratory testing data in the forensic report. For the applicability, the proposed approach is applied to the Hang-ju Grand Bridge, which collapsed during construction, and compared with deterministic approach
Creep-Fatigue Failure Diagnosis

Science.gov (United States)

Holdsworth, Stuart

2015-01-01

Failure diagnosis invariably involves consideration of both associated material condition and the results of a mechanical analysis of prior operating history. This Review focuses on these aspects with particular reference to creep-fatigue failure diagnosis. Creep-fatigue cracking can be due to a spectrum of loading conditions ranging from pure cyclic to mainly steady loading with infrequent off-load transients. These require a range of mechanical analysis approaches, a number of which are reviewed. The microstructural information revealing material condition can vary with alloy class. In practice, the detail of the consequent cracking mechanism(s) can be camouflaged by oxidation at high temperatures, although the presence of oxide on fracture surfaces can be used to date events leading to failure. Routine laboratory specimen post-test examination is strongly recommended to characterise the detail of deformation and damage accumulation under known and well-controlled loading conditions to improve the effectiveness and efficiency of failure diagnosis. PMID:28793676
Learning from and for rare floods in Dresden – how public officials interpret damage simulation results at the building type level

Directory of Open Access Journals (Sweden)

Hutter Gerard

2016-01-01

Full Text Available Public officials in Dresden are concerned about learning from and for rare flood events like the Elbe river flood in August 2002. This is interesting because research on individual as well as organizational learning from rare events indicates that this kind of learning faces significant difficulties (e.g., overestimation of rare events for decision-making based on “emotionalized event experience”. Up to now, only little is known what and how public officials in Dresden specifically learn from and for rare floods. Therefore, the paper follows an exploratory purpose in line with principles of qualitative social research. Firstly, the paper explores dealing with rare floods with reference to a conceptual framework that highlights relations between regulative, normative, and cognitive institutions on the one hand and learning of public officials on the other. Secondly, it adopts a single case study design in Dresden with embedded sub-cases that are defined with reference to organizations of FRM. The case study shows, among others, that regulations like the Floods Directive are important for justifying FRM with regard to rare flood events which is less obvious than it sounds. However, public officials display different interpretations of the term “rare flood event”, for instance, in the context of analysing the consequences of floods on the building stock. Furthermore, the case study findings indicate that public officials may follow alternative approaches to sustain commitment in the context of rare flood events (systematic versus pragmatic approach.
Data collection on component malfunctions and failures of JET ICRH system

International Nuclear Information System (INIS)

Pinna, T.; Cambi, G.

2007-01-01

The objective of the activity was to collect and analyse data coming out from operating experiences gained in the Joint European Torus (JET) for the Ion Cyclotron Resonance Heating (ICRH) system in order to enrich the data collection on failures of components used in fusion facilities. Alarms/Failures and malfunctions occurred in the years of operations from March 1996 to November 2005, including information on failure modes and, where possible, causes of the failures, have been identified. Beyond information on failures and alarms events, also data related to crowbar events have been collected. About 3400 events classified as alarms or failures related to specific components or sub-systems were identified by analysing the 25 hand-written logbooks made available by the ICRH operation staff. Information about the JET pulses in which the ICRH system was operated has been extracted from the tick sheets covering the whole considered time interval. 20 hand written tick sheets cover the period from March 1996 to middle May 2003, while tick sheets recorded as excel files cover the period from May 2003 to November 2005. By analysing the tick sheets it results that the ICRH was operated during about 12000 plasma pulses. Main statistical values, such as rates of alarms/failures and corresponding standard errors and confidence intervals, have been estimated. Failure rates of systems and components have been evaluated both with regard to the ICRH operation pulses and operating days (days in which at least one ICRH module was requested to operate). Failure probabilities on demand have been evaluated with regard to number of pulses operated. Some of the results are the following: - The highest number of alarms/failures (1243) appears to be related to Erratic /No-output of the Instrumentation and Control (I and C) apparatus, followed by faults (829) of the Tetrode circuits, by faults (466) of the High Voltage Power Supply system and by faults (428) of the Tuning elements. - The
Consequences assessment for fuel channel failure with consequential moderator drain

International Nuclear Information System (INIS)

Wahba, N.N.; Bayoumi, M.H.

2002-01-01

This paper documents the consequences of spontaneous pressure tube/consequential calandria tube rupture followed by the ejection of end fittings (as a result of guillotine failure of pressure tube) leading to the drain of the moderator. The event is postulated to occur in conjunction with an independent failure of Emergency Coolant Injection System (ECIS). The results of the detailed consequence assessments are used to propose a course of action to mitigate the consequences of such an event. A methodology based on a lumped-parameter model was developed to assess the consequences of the postulated event. (author)
Seismic ratchet-fatigue failure of piping systems

International Nuclear Information System (INIS)

Severud, L.K.; Anderson, M.J.; Lindquist, M.R.; Weiner, E.O.

1987-01-01

Failures of piping systems during earthquakes have been rare. Those that have failed were either made of brittle material such as cast iron, were rigid systems between major components where component relative seismic motions tore the pipe out of the component, or were high pressure systems where a ratchet-fatigue fracture followed a local bulging of the pipe diameter. Tests to failure of an unpressurized 3-inch and a pressurized 6-inch diameter carbon steel nuclear pipe systems subjected to high-level shaking have been accomplished. The high-level shaking loads needed to cause failure were much higher than ASME Code rules would permit with present design limits. Failure analyses of these tests are presented and correlated to the test results. It was found that failure of the unpressurized system could be correlated well with standard ASME type fatigue analysis predictions. Moreover, the pressurized system failure occured in significantly less load cycles than predicted by standard fatigue analysis. However, a ratchet-fatigue and ductility exhaustion analysis of the pressurized system did correlate reasonably well. These findings indicate modifications to design analysis methods and the present ASME Code piping design rules to reduce unneeded conservatisms and to cover the ratchet-fatigue failure mode may be appropriate
Three cases of respiratory failure after I-131 radioiodine therapy

International Nuclear Information System (INIS)

Watanabe, Ken; Uchiyama, Masayuki; Fukuda, Kunihiko

2016-01-01

We report three cases of respiratory failure after I-131 radioiodine therapy. All cases involved relapsed cervical lesions, and two showed edema of the larynx. Emergency tracheostomy was performed to treat the respiratory failure in one case while the others were treated conservatively. All patients showed improvements without after-effects. Patients who undergo I-131 radioiodine therapy, especially those with cervical lesions, should be carefully monitored for this rare complication after treatment. (author)
Dam failure analysis for the Lago El Guineo Dam, Orocovis, Puerto Rico

Science.gov (United States)

Gómez-Fragoso, Julieta; Heriberto Torres-Sierra,

2016-08-09

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers.The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC–HMS) and Hydrologic Engineering Center’s River Analysis System (HEC–RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model.Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are
Initiating events frequency determination

International Nuclear Information System (INIS)

Simic, Z.; Mikulicic, V.; Vukovic, I.

2004-01-01

The paper describes work performed for the Nuclear Power Station (NPS). Work is related to the periodic initiating events frequency update for the Probabilistic Safety Assessment (PSA). Data for all relevant NPS initiating events (IE) were reviewed. The main focus was on events occurring during most recent operating history (i.e., last four years). The final IE frequencies were estimated by incorporating both NPS experience and nuclear industry experience. Each event was categorized according to NPS individual plant examination (IPE) initiating events grouping approach. For the majority of the IE groups, few, or no events have occurred at the NPS. For those IE groups with few or no NPS events, the final estimate was made by means of a Bayesian update with general nuclear industry values. Exceptions are rare loss-of-coolant-accidents (LOCA) events, where evaluation of engineering aspects is used in order to determine frequency.(author)
Chronic renal failure secondary to polysubstance misuse | Odigie ...

African Journals Online (AJOL)

Chronic Renal Failure [CRF] is a progressive irreversible deterioration in renal function with a spectrum ranging from biochemical abnormalities [azotemia] to clinically evident abnormalities [uraemia] and end stage renal disease [ESRD]. The purpose of this paper is to highlight the significance of rare causes of CRF in the ...
Measurements of reciprocity law failure in green-sensitive X-ray films.

Science.gov (United States)

Arnold, B A; Eisenberg, H; Bjärngard, B E

1978-02-01

Reciprocity law failure was measured for four brands of medical x-ray films exposed with intensifying screens. Three of the films are green light-sensitized for use in combination with green light-emitting rare-earth screens. These films showed larger reciprocity failure effects than one conventional blue-sensitive film, Dupont Cronex-2. Development conditions had a small effect on reciprocity failure. As part of the investigation, a detector was constructed with a response that accurately monitors the light emission from the double screen-cassette combination over a wide range of x-ray photon energies.
Phlegmonous enteritis in a patient with congestive heart failure and colon cancer

Energy Technology Data Exchange (ETDEWEB)

Namkung, Sook; Yoo, Yoon Sik; Hwang, Im Kyung; Kim, Bong Soo; Bae, Sang Hoon; Choi, Young Hee [Hallym University, Chuncheon (Korea, Republic of)

2001-12-01

Phlegmonous enteritis is a rare infective inflammatory disease of the intestine, predominantly involving the submucosal layer. It is difficult to diagnose and often fatal. Its association with alcoholism and various liver diseases, although rarely reported, is well documented. We report a case of phlegmonous enteritis in a male patient with congestive heart failure and colon cancer, and describe the ultrasonographic and CT findings.
An Overview of Rare Earth Science and Technology

Science.gov (United States)

Gschneidner, Karl, Jr.

2012-02-01

Currently rare earth science and technology is robust: this includes all the major branches of science -- biochemistry, chemistry, materials and physics. There are, however, currently some anomalies and distortions especially in the technology and applications sector of the rare earth field, which is caused by the dominance of China on the sales of rare earths and rare earth containing products. For the past 5 to 10 years ˜95% of rare earths utilized in commerce came from China. Although Chinese actions have lead to sudden and large price spikes and export embargoes, the rare earths are still available but at a higher cost. The start up of production in 2011 at mines in the USA and Australia will alleviate this situation in about two years. Basic and applied research on the condensed matter physics/materials science has hardly been impacted by these events, but new research opportunities are opening up especially with regard to the USA's military and energy security. Magnets seems to be the hottest topic, but research on battery materials, phosphors and catalysts are also (or should be) strongly considered.
Data needs for common cause failure analysis

International Nuclear Information System (INIS)

Parry, G.W.; Paula, H.M.; Rasmuson, D.; Whitehead, D.

1990-01-01

The procedures guide for common cause failure analysis published jointly by USNRC and EPRI requires a detailed historical event analysis. Recent work on the further development of the cause-defense picture of common cause failures introduced in that guide identified the information that is necessary to perform the detailed analysis in an objective manner. This paper summarizes these information needs

Piping failures in United States nuclear power plants 1961-1995

International Nuclear Information System (INIS)

Bush, S.H.; Do, M.J.; Slavich, A.L.; Chockie, A.D.

1996-01-01

Over 1500 reported piping failures were identified and summarized based on an extensive review of tens of thousands of event reports that have been submitted to the US regulatory agencies over the last 35 years. The data base contains only piping failures; failures in vessels, pumps, valves and steam generators or any cracks that were not through-wall are not included. It was observed that there has been a marked decrease in the number of failures after 1983 for almost all sizes of pipes. This is likely due to the changes in the reporting requirements at that time and the corrective actions taken by utilities to minimize fatigue failures of small lines and IGSCC in BWRs. One failure mechanism that continues to occur is erosion-corrosion, which accounts for most of the ruptures reported and probably is responsible for the absence of downward trends in ruptures. Fatigue-vibration is also a significant contributor to piping failures. However, most of such events occur in lines approx. one inch or less in diameter. Together, erosion-corrosion and fatigue-vibration account for over 43 per cent of the failures. The overwhelming majority of failures have been leaks, over half the failures occurred in pipes with a diameter of one inch or less. Included in the report is a listing of the number of welds in various systems in LWRs
Destructive Single-Event Effects in Diodes

Science.gov (United States)

Casey, Megan C.; Lauenstein, Jean-Marie; Campola, Michael J.; Wilcox, Edward P.; Phan, Anthony M.; Label, Kenneth A.

2017-01-01

In this work, we discuss the observed single-event effects in a variety of types of diodes. In addition, we conduct failure analysis on several Schottky diodes that were heavy-ion irradiated. High- and low-magnitude optical microscope images, infrared camera images, and scanning electron microscope images are used to identify and describe the failure locations.
Emotions in memories of success and failure: a cultural perspective.

Science.gov (United States)

Zhang, Meng; Cross, Susan E

2011-08-01

Americans and Chinese tend to behave differently in response to success and failure: Americans tend to persist on a task after success, whereas Chinese tend to persist after failure. This study examined whether cultural differences in emotional reactions to success and failure account for these differences. American and Chinese students recalled personal success and failure events, evaluated the primary emotion evoked by the event, and responded to measures of concerns, appraisals, and willingness to try the same task again. Americans were more likely than Chinese to report that their success enhanced their self-esteem. Chinese were more likely than Americans to estimate that their success would make others jealous and enhance others' respect for their family. Chinese, compared to Americans, viewed failures as more tolerable, as less problematic for their goals, and as less damaging to their self-esteem. Culture moderated the relations between these components of emotion and willingness to try the task again. In short, culturally framed emotional reactions to success and failure result in different patterns of anticipated self-regulation. 2011 APA, all rights reserved
Control rod trip failures; Salem 1, the cause, response, and potential fixes

International Nuclear Information System (INIS)

Hall, R.E.; Boccio, J.L.; Luckas, W.J.

1984-01-01

This chapter presents a systems and reliability analysis of recent nuclear reactor control rod failure-to-trip (or scram) events that have been experienced in the US commercial nuclear industry. The operational factors of hardware, procedures, and human error are considered in the analysis of transients without scram. The 1980 Browns Ferry 3 scram system failure is analyzed to contrast the two 1983 Salem 1 events. The details of the Salem control rod failure to trip are investigated and used to calculate the reactor protection system unavailabilities. The internal reactor trip breaker logic is reviewed as related to the Westinghouse DB-50 breaker application. The impact of test and maintenance on system challenges is discussed. It is concluded that although the failure to trip or scram represents a single class of initiators, the actual events of each transient are operationally unique and require individual human responses
Seeing failure in your life: Imagery perspective determines whether self-esteem shapes reactions to recalled and imagined failure.

Science.gov (United States)

Libby, Lisa K; Valenti, Greta; Pfent, Alison; Eibach, Richard P

2011-12-01

The present research reveals that when it comes to recalling and imagining failure in one's life, changing how one looks at the event can change its impact on well-being; however, the nature of the effect depends on an aspect of one's self-concept, namely, self-esteem. Five studies measured or manipulated the visual perspective (internal first-person vs. external third-person) individuals used to mentally image recalled or imagined personal failures. It has been proposed that imagery perspective determines whether people's reactions to an event are shaped bottom-up by concrete features of the event (first-person) or top-down by their self-concept (third-person; L. K. Libby & R. P. Eibach, 2011b). Evidence suggests that differences in the self-concepts of individuals with low and high self-esteem (LSEs and HSEs) are responsible for self-esteem differences in reaction to failure, leading LSEs to have more negative thoughts and feelings about themselves (e.g., M. H. Kernis, J. Brockner, & B. S. Frankel, 1989). Thus, the authors predicted, and found, that low self-esteem was associated with greater overgeneralization--operationalized as negativity in accessible self-knowledge and feelings of shame--only when participants had pictured failure from the third-person perspective and not from the first-person. Further, picturing failure from the third-person, rather than first-person, perspective, increased shame and the negativity of accessible knowledge among LSEs, whereas it decreased shame among HSEs. Results help to distinguish between different theoretical accounts of how imagery perspective functions and have implications for the study of top-down and bottom-up influences on self-judgment and emotion, as well as for the role of perspective and abstraction in coping.
Structures for common-cause failure analysis

International Nuclear Information System (INIS)

Vaurio, J.K.

1981-01-01

Common-cause failure methodology and terminology have been reviewed and structured to provide a systematical basis for addressing and developing models and methods for quantification. The structure is based on (1) a specific set of definitions, (2) categories based on the way faults are attributable to a common cause, and (3) classes based on the time of entry and the time of elimination of the faults. The failure events are then characterized by their likelihood or frequency and the average residence time. The structure provides a basis for selecting computational models, collecting and evaluating data and assessing the importance of various failure types, and for developing effective defences against common-cause failure. The relationships of this and several other structures are described
Quantum Field Theory of Black-Swan Events

Science.gov (United States)

Kleinert, H.

2014-05-01

Free and weakly interacting particles are described by a second-quantized nonlinear Schrödinger equation, or relativistic versions of it. They describe Gaussian random walks with collisions. By contrast, the fields of strongly interacting particles are governed by effective actions, whose extremum yields fractional field equations. Their particle orbits perform universal Lévy walks with heavy tails, in which rare events are much more frequent than in Gaussian random walks. Such rare events are observed in exceptionally strong windgusts, monster or rogue waves, earthquakes, and financial crashes. While earthquakes may destroy entire cities, the latter have the potential of devastating entire economies.
Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

Energy Technology Data Exchange (ETDEWEB)

Lee C. Cadwallader

2010-06-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.
Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

Energy Technology Data Exchange (ETDEWEB)

Lee C. Cadwallader

2007-08-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with “generic” component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance.
Preliminary Failure Modes and Effects Analysis of the US DCLL Test Blanket Module

International Nuclear Information System (INIS)

Lee C. Cadwallader

2007-01-01

This report presents the results of a preliminary failure modes and effects analysis (FMEA) of a small tritium-breeding test blanket module design for the International Thermonuclear Experimental Reactor. The FMEA was quantified with 'generic' component failure rate data, and the failure events are binned into postulated initiating event families and frequency categories for safety assessment. An appendix to this report contains repair time data to support an occupational radiation exposure assessment for test blanket module maintenance
The Fourth Branchial Complex Anomaly: A Rare Clinical Entity

OpenAIRE

Patel, Alpen B.; Hinni, Michael L.

2011-01-01

Fourth branchial pouch anomalies are rare congenital disorders of the neck and are a consequence of abnormal development of the branchial apparatus during embryogenesis. Failure to appropriately recognize these anomalies may result in misdiagnosis, insufficient treatment, and continued recurrence. Here, we present an unique presentation of two cases, describe their diagnosis, clinical course, and management, and review the literature regarding these interesting anomalies.
The fourth branchial complex anomaly: a rare clinical entity.

Science.gov (United States)

Patel, Alpen B; Hinni, Michael L

2011-01-01

Fourth branchial pouch anomalies are rare congenital disorders of the neck and are a consequence of abnormal development of the branchial apparatus during embryogenesis. Failure to appropriately recognize these anomalies may result in misdiagnosis, insufficient treatment, and continued recurrence. Here, we present an unique presentation of two cases, describe their diagnosis, clinical course, and management, and review the literature regarding these interesting anomalies.
Micromechanical local approach to brittle failure in bainite high resolution polycrystals: A short presentation

International Nuclear Information System (INIS)

N'Guyen, C.N.; Osipov, N.; Cailletaud, G.; Barbe, F.; Marini, B.; Petry, C.

2012-01-01

The problem of determining the probability of failure in a brittle material from a micromechanical local approach has recently been addressed in few works, all related to bainite polycrystals at different temperatures and states of irradiation. They have separately paved the ground for a full-field modelling with high realism in terms of constitutive modelling and microstructural morphology. This work first contributes to enhance this realism by assembling the most pertinent/valuable characteristics (dislocation density based model, large deformation framework, fully controlled triaxiality conditions, explicit microstructure representation of grains and sub-grains,... ) and by accounting for a statistically representative Volume Element; this condition indeed must be fulfilled in order to capture rare events like brittle micro-fractures which, in the stress analysis, correspond to the tails of distribution curves. The second original contribution of this work concerns the methodology for determining fracture probabilities: rather than classically - and abruptly - considering a polycrystal as broken as soon as an elementary link (grain or sub-grain) has failed, the possibility of microcrack arrest at microstructural barriers is introduced, which enables to determine the probability of polycrystal failure according to different scenarios of multiple micro-fractures. (authors)
'Case reporting of rare adverse events in otolaryngology': can we defend the case report?

LENUS (Irish Health Repository)

Dias, Andrew

2012-01-31

The study of errors in medicine has proliferated since the publication of The Institute of Medicine Report \\'TO ERR IS HUMAN\\' in 2000. Case nuances and process of care issues are valuable areas to explore if the goal is to provide the health care worker with the knowledge to avoid future errors. Meta-analysis and randomized controlled trials provide a large data base of evidence towards improvement and opportunities, but it is suggested that case reports can still provide valuable clinical information. The aim is to use the published literature to produce a series of rare harm case reports in E.N.T. The methods include systematic literature review. Journals searched in PUBMED were 60. Rare harm case obtained from the search were 5,322. Rare harm case reports not reported in any other form of evidence-based medicine were 40. Yes, the case report can be defended as it is an important pillar of evidence-based medicine.
Gallbladder Volvulus: A rare cause of acute abdomen. A case report ...

African Journals Online (AJOL)

Gallbladder volvulus is a rare but serious event. Described for the first time by Wendal in 1898, the condition is the result of a congenital anomaly, in which the gallbladder is suspended by a mesentery which allows the rare possibility of its torsion which, when not handled urgently, results in gangrene and even peritonitis.
A Rare Cause of Acute Renal Failure: Fenofibrate-Induced Rhabdomyolysis

Directory of Open Access Journals (Sweden)

Ferhat Icme

2013-08-01

Full Text Available Fibrates are derivative of fibric acid and broad spectrum drugs which are commonly used in the treatment of dyslipidemia and hypertriglyceridemia. Side effects are often related with striated muscles, kidney and liver. Rhabdomyolysis developing with striated muscle destruction is potentially the most lethal of these side effects. Although several case reports of rhabdomyolysis have been reported due to the combination of statin and fenofibrate, fenofibrate alone rarely causes rhabdomyolysis. The purposes of this paper are to present a patient whom we diagnosed with acute renal injury due to use of fenofibrate in order to emphasize the importance of questioning drugs which have been used, and to review management of rhabdomyolysis due to fenofibrate use. [Cukurova Med J 2013; 38(4.000: 800-804
Defense-in-depth and diversity evaluation to cope with design bases events concurrent with common mode failure in digital plant protection system for KNGR

International Nuclear Information System (INIS)

Shin, Lee Cheol; Park, Chan Eok; Jin, Choi Chul; Tae, Seo Jong

2001-01-01

The Korean Next Generation Reactor (KNGR) has been evolved to adopt an advanced design feature, a digital Plant Protection System (PPS) as an effort of enhancing reliability and safety of the plant. Although the digital PPS can be designed with high reliability, it is considered to be vulnerable to the Common Mode Failure (CMF) in the system software resulting in a total loss of the built-in hardware redundancy. Therefore, a comprehensive evaluation has been performed to demonstrate the intrinsic capability of the KNGR design in coping with the design basis events concurrent with CMF in the digital PPS. Instead of the conservative bounding analysis methodology, a best-estimate analysis methodology has been developed and utilized since the design basis events accompanied by CMF in the digital PPS are categorized as beyond design bases events. A variety of diverse means such as Alternate Protection System (APS), process control systems, and timely operator actions have been verified to be effective in mitigating the design basis events with CMF in the digital PPS
Common cause failures of reactor pressure components

International Nuclear Information System (INIS)

Mankamo, T.

1978-01-01

The common cause failure is defined as a multiple failure event due to a common cause. The existence of common failure causes may ruin the potential advantages of applying redundancy for reliability improvement. Examples relevant to large mechanical components are presented. Preventive measures against common cause failures, such as physical separation, equipment diversity, quality assurance, and feedback from experience are discussed. Despite the large number of potential interdependencies, the analysis of common cause failures can be done within the framework of conventional reliability analysis, utilizing, for example, the method of deriving minimal cut sets from a system fault tree. Tools for the description and evaluation of dependencies between components are discussed: these include the model of conditional failure causes that are common to many components, and evaluation of the reliability of redundant components subjected to a common load. (author)
Acute adrenal failure as the presenting feature of primary antiphospholipid syndrome in a child

Directory of Open Access Journals (Sweden)

Improda Nicola

2012-09-01

Full Text Available Abstract Introduction Antiphospholipid syndrome (APS is characterized by recurrent arterial and venous thrombosis and detection of antiphospholipid antibodies (aPLs. This syndrome may be associated with connective tissue disorders, or with malignancies, but it may also appear in isolated form (primary APS. We report on a pediatric patient presenting with acute adrenal failure as the first manifestation of primary APS. Case report A previously healthy 11-year-old boy developed fever, abdominal pain, and vomiting. An abdominal computed tomography scan showed nodular lesions in the adrenal glands. He was referred to our Department and a diagnosis of APS and acute adrenal failure was considered, based on positive aPLs (IgG and IgM, elevated ACTH levels and low cortisol levels. Other features were anemia, thrombocytopenia, elevated inflammatory parameters, hypergammaglobulinemia, prolonged partial thromboplastin time, positive antinuclear, anticardiolipin, anti-platelet antibodies, with negative double-stranded DNA antibodies. Lupus anticoagulant and Coomb’s tests were positive. MRI revealed a bilateral adrenal hemorrhage. A treatment with intravenous metylprednisolone, followed by oral prednisone and anticoagulant, was started, resulting in a progressive improvement. After 2 months he also showed hyponatremia and elevated renine levels, indicating a mineralcocorticoid deficiency, requiring fludrocortisones therapy. Conclusion The development of acute adrenal failure from bilateral adrenal haemorrhage in the context of APS is a rare but life-threatening event that should be promptly recognized and treated. Moreover, this case emphasizes the importance of the assessment of aPLs in patients with acute adrenal failure in the context of an autoreaction.
A rare case of peripartum cardiomyopathy posted for caesarean section

Directory of Open Access Journals (Sweden)

Nalini Kotekar

2007-01-01

Full Text Available Post Partum Cardiomyopathy (PPCM is a relatively rare form of heart failure associated with pregnancy. It was recognized first in the 19th century by Ritchie and is defined as the onset of acute heart failure in the last trimester or early post partum period in the absence of infections, metabolic, toxic, ischaemic or valvular causes of myocardial dysfunction. Prognosis depends on the degree of cardiomegaly at presentation and in the following 6 months. Initial high risk period carries a mortality of 25 to 50%. Keeping in mind the reduced contractility and ejection fraction with ventricular dilatation proceeding to cardiac failure, the anesthesiologist managing a case of PPCM faces the challenge of avoiding myocardial depression, hypovolemia and increased SVR, all of which may be hazardous

A rare case of diaphragmatic paralysis due to isolated phrenic nerve ...

African Journals Online (AJOL)

2008-11-04

Nov 4, 2008 ... Isolated phrenic nerve palsy is a rare condition resulting from birth injury, with many possible complications such as diaphragmatic paralysis, pulmonary infection, chronic lung disease, growth failure and even death.1-3 I report a case of neonatal isolated phrenic nerve palsy in an infant delivered.
Unusual case of failure to thrive: Type III Bartter syndrome.

Science.gov (United States)

Agrawal, S; Subedi, K; Ray, P; Rayamajhi, A

2016-09-01

Bartter syndrome Type III is a rare autosomal recessive disorder resulting from an inherited defect in the thick ascending limb of the loop of henle of the nephrons in kidney. The typical clinical manifestations in childhood are failure to thrive and recurrent episodes of vomiting. Typical laboratory findings which help in the diagnosis are hypokalemic metabolic alkalosis, hypomagnesemia and hypercalciuria. We report a case of Type III Bartter syndrome not responding to repeated conventional treatment of failure to thrive.
Characterization and prediction of extreme events in turbulence

Science.gov (United States)

Fonda, Enrico; Iyer, Kartik P.; Sreenivasan, Katepalli R.

2017-11-01

Extreme events in Nature such as tornadoes, large floods and strong earthquakes are rare but can have devastating consequences. The predictability of these events is very limited at present. Extreme events in turbulence are the very large events in small scales that are intermittent in character. We examine events in energy dissipation rate and enstrophy which are several tens to hundreds to thousands of times the mean value. To this end we use our DNS database of homogeneous and isotropic turbulence with Taylor Reynolds numbers spanning a decade, computed with different small scale resolutions and different box sizes, and study the predictability of these events using machine learning. We start with an aggressive data augmentation to virtually increase the number of these rare events by two orders of magnitude and train a deep convolutional neural network to predict their occurrence in an independent data set. The goal of the work is to explore whether extreme events can be predicted with greater assurance than can be done by conventional methods (e.g., D.A. Donzis & K.R. Sreenivasan, J. Fluid Mech. 647, 13-26, 2010).
International Context Regarding Application of Single Failure Criterion For New Reactors

International Nuclear Information System (INIS)

Basic, I.; Vrbanic, I.

2016-01-01

The Single Failure Criterion (SFC) ensures reliable performance of safety systems in nuclear power plants in response to design basis initiating events. The SFC, basically, requires that the system must be capable of performing its task in the presence of any single failure. The capability of a system to perform its design function in the presence of a single failure could be threatened by a common cause failure such as a fire, flood, or human intervention or by any other cause with potential to induce multiple failures. When applied to plant's response to a postulated design-basis initiating event, the SFC usually represents a requirement that particular safety system performs its safety functions as designed under the conditions which can include: All failures caused by a single failure; All identifiable but non-detectable failures, including those in the non-tested components; All failures and spurious system actions that cause (or are caused by) the postulated event. The paper provides an overview of the regulatory design requirements for new reactors addressing Single Failure Criterion (SFC) in accordance to international best-practices, particularly considering the SCF relation to in-service testing, maintenance, repair, inspection and monitoring of systems, structures and components important to safety. The paper discusses the comparison of the current SFC requirements and guidelines published by the IAEA, WENRA, EUR and nuclear regulators in the United States, United Kingdom, Russia, Korea, Japan, China and Finland. Also, paper addresses the application of SFC requirements in design; considerations for testing, maintenance, repair, inspection and monitoring; allowable equipment outage times; exemptions to SFC requirements; and analysis for SFC application to two-, three- and four-train systems and applications for small and modular reactors. (author).
Study of radiation background at various high altitude locations in preparation for rare event search in cosmic rays

Energy Technology Data Exchange (ETDEWEB)

Bhattacharyya, R.; Dey, S.; Ghosh, Sanjay K.; Maulik, A.; Raha, Sibaji; Syam, D., E-mail: rupamoy@gmail.com, E-mail: dey_s2001@yahoo.com, E-mail: sanjay@jcbose.ac.in, E-mail: atanu.maulik@jcbose.ac.in, E-mail: sibaji.raha@jcbose.ac.in, E-mail: syam.debapriyo@gmail.com [Centre for Astroparticle Physics and Space Science, Bose Institute, Block-EN, Sector-V, Kolkata-700091 (India)

2017-04-01

Various phenomenological models presented over the years have hinted at the possible presence of strangelets, which are nuggets of Strange Quark Matter (SQM), in cosmic rays. One way to search for such rare events is through the deployment of large area Nuclear Track Detector (NTD) arrays at high mountain altitudes. Before the deployment of any such array can begin, a detailed study of the radiation background is essential. Also, a proper understanding of the response of detectors exposed to extreme weather conditions is necessary. With that aim, pilot studies were carried out at various high altitude locations in India such as Darjeeling (2200 m a.m.s.l), Ooty (2200 m a.m.s.l) and Hanle (4500 m a.m.s.l). Small arrays of CR-39 as well as high threshold Polyethylene Terephthalate (PET) detectors were given open air exposures for periods ranging from three months to two years. The findings of such studies are reported in this paper.
Analysis of the reliability of quality assurance of welded nuclear pressure vessels with regard to catastrophic failure

Energy Technology Data Exchange (ETDEWEB)

Ostberg, G [Lund Institute of Technology, Dept. of Materials Engineering (Sweden); Klingenstierna, B [FTL, Military Electronics Laboratory, National Defence Research Institute, Stockholm (Sweden); Sjoberg, L [Goteborg Univ., Dept. of Psychology (Sweden)

1976-07-01

The project is described as an analysis of the reliability of quality assurance of welded nuclear pressure vessels with regard to catastrophic failure. Its scope extends both beyond previous statistical evaluations of the risk of catastrophic failure, beyond previous studies of human malfunction, and beyond current studies of probabilistic fracture mechanics. The latter deal only with 'normal' data and 'normal' processes and procedures according to established rules and regulations, where as the present study concerns deficiencies or more or less complete fallacies of normal procedures and processes. Hopefully such events will prove to be rare enough to be characterized as 'unique'; this, in turn, means that the result of the investigation is not a new statistical figure but rather a survey of types and frequencies of errors and error-producing conditions. The emphasis is on the main pressure vessel; related information on the primary circuit is included, only when this can be done without excessive effort or costs. The avenues of approach in terms of technical-academic disciplines are reliability techniques and the psychology of analysis work and control processes.
Failure to Follow Written Procedures

Science.gov (United States)

2017-12-01

Most tasks in aviation have a mandated written procedure to be followed specifically under the Code of Federal Regulations (CFR) Part 14, Section 43.13(a). However, the incidence of Failure to Follow Procedure (FFP) events continues to be a major iss...
Analysis of failures in concrete containments

International Nuclear Information System (INIS)

Moreno-Gonzalez, A.

1989-09-01

The function of Containment, in an accident event, is to avoid the release of radioactive substances into the surroundings. Containment failure, therefore, is defined as the appearance of leak paths to the external environment. These leak paths may appear either as a result of loss of leaktightness due to degradation of design conditions or structural failure with containment material break. This document is a survey of the state of the art of Containment Failure Analysis. It gives a detailed description of all failure mechanisms, indicating all the possible failure modes and their causes, right from failure resulting from degradation of the materials to structural failure and linear breake failure. Following the description of failure modes, possible failure criteria are identified, with special emphasis on structural failure criteria. These criteria have been obtained not only from existing codes but also from the latest experimental results. A chapter has been dedicated exclusively to failure criteria in conventional structures, for the purpose of evaluating the possibility of application to the case of containment. As the structural behaviour of the containment building is very complex, it is not possible to define failure through a single parameter. It is therefore advisable to define a methodology for containment failure analysis which could be applied to a particular containment. This methodology should include prevailing load and material conditions together with the behaviour of complex conditions such as the liner-anchorage-cracked concrete interaction
ICDE project report: collection and analysis of common-cause failures of batteries

International Nuclear Information System (INIS)

2003-12-01

This report documents a study performed on the set of Common Cause Failure (CCF) events of batteries (BT). the events studied here were derived from the International CCF Data Exchange (ICDE) database, with contributions from organizations from several countries. 50 events in the ICDE database were studied by tabulating the data and observing the trends. The data span a period from 1980 through 2000. The database contains general information about event attributes such as root cause, coupling factor, common cause component group (CCCG) size, and corrective action. The objective of the report was also to develop the failure mechanisms and phenomena involved in the events, their relationship to the root causes, and possibilities for improvement
Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

International Nuclear Information System (INIS)

Volynets, Oleksandr

2012-01-01

Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.
Methods to improve and understand the sensitivity of high purity germanium detectors for searches of rare events

Energy Technology Data Exchange (ETDEWEB)

Volynets, Oleksandr

2012-07-27

Observation of neutrinoless double beta-decay could answer fundamental questions on the nature of neutrinos. High purity germanium detectors are well suited to search for this rare process in germanium. Successful operation of such experiments requires a good understanding of the detectors and the sources of background. Possible background sources not considered before in the presently running GERDA high purity germanium detector experiment were studied. Pulse shape analysis using artificial neural networks was used to distinguish between signal-like and background-like events. Pulse shape simulation was used to investigate systematic effects influencing the efficiency of the method. Possibilities to localize the origin of unwanted radiation using Compton back-tracking in a granular detector system were examined. Systematic effects in high purity germanium detectors influencing their performance have been further investigated using segmented detectors. The behavior of the detector response at different operational temperatures was studied. The anisotropy effects due to the crystallographic structure of germanium were facilitated in a novel way to determine the orientation of the crystallographic axes.
Hypoxemic Respiratory Failure from Acute Respiratory Distress Syndrome Secondary to Leptospirosis

Directory of Open Access Journals (Sweden)

Shannon M. Fernando

2017-01-01

Full Text Available Acute respiratory distress syndrome (ARDS, characterized by hypoxemic respiratory failure, is associated with a mortality of 30–50% and is precipitated by both direct and indirect pulmonary insults. Treatment is largely supportive, consisting of lung protective ventilation and thereby necessitating Intensive Care Unit (ICU admission. The most common precipitant is community-acquired bacterial pneumonia, but other putative pathogens include viruses and fungi. On rare occasions, ARDS can be secondary to tropical disease. Accordingly, a history should include travel to endemic regions. Leptospirosis is a zoonotic disease most common in the tropics and typically associated with mild pulmonary complications. We describe a case of a 25-year-old male with undiagnosed leptospirosis, presenting with fever and severe hypoxemic respiratory failure, returning from a Costa Rican holiday. There was no other organ failure. He was intubated and received lung protective ventilation. His condition improved after ampicillin and penicillin G were added empirically. This case illustrates the rare complication of ARDS from leptospirosis, the importance of taking a travel history, and the need for empiric therapy because of diagnostic delay.
Rare case-series of electrocautery burn following off-pump coronary artery bypass grafting

Science.gov (United States)

Sabzi, Feridoun; Niazi, Mojtaba; Ahmadi, Alireza

2014-01-01

Abstract: With an increasing number of off-pump coronary artery surgery procedures in high-risk patients with coagulopathy, including renal failure, hepatic failure and anticoagulant drug-using patients, the frequency of related complications such as repeated exploration for bleeding is also increasing. The associated co-morbidity and repeated use of electrocautery in postoperative bleeding leaves patients susceptible to electrocautery ulcers. In this case series, rare cases of cautery burn with unique causative mechanisms are described. PMID:23669602
Rare events in many-body systems: reactive paths and reaction constants for structural transitions

International Nuclear Information System (INIS)

Picciani, M.

2012-01-01

This PhD thesis deals with the study of fundamental physics phenomena, with applications to nuclear materials of interest. We have developed methods for the study of rare events related to thermally activated structural transitions in many body systems. The first method involves the numerical simulation of the probability current associated with reactive paths. After deriving the evolution equations for the probability current, a Diffusion Monte Carlo algorithm is implemented in order to sample this current. This technique, called Transition Current Sampling was applied to the study of structural transitions in a cluster of 38 atoms with Lennard-Jones potential (LJ-38). A second algorithm, called Transition Path Sampling with local Lyapunov bias (LyTPS), was then developed. LyTPS calculates reaction rates at finite temperature by following the transition state theory. A statistical bias based on the maximum local Lyapunov exponents is introduced to accelerate the sampling of reactive trajectories. To extract the value of the equilibrium reaction constants obtained from LyTPS, we use the Multistate Bennett Acceptance Ratio. We again validate this method on the LJ-38 cluster. LyTPS is then used to calculate migration constants for vacancies and divacancies in the α-Iron, and the associated migration entropy. These constants are used as input parameter for codes modeling the kinetic evolution after irradiation (First Passage Kinetic Monte Carlo) to reproduce numerically resistivity recovery experiments in α-Iron. (author) [fr
Correlation model to analyze dependent failures for probabilistic risk assessment

International Nuclear Information System (INIS)

Dezfuli, H.

1985-01-01

A methodology is formulated to study the dependent (correlated) failures of various abnormal events in nuclear power plants. This methodology uses correlation analysis is a means for predicting and quantifying the dependent failures. Appropriate techniques are also developed to incorporate the dependent failure in quantifying fault trees and accident sequences. The uncertainty associated with each estimation in all of the developed techniques is addressed and quantified. To identify the relative importance of the degree of dependency (correlation) among events and to incorporate these dependencies in the quantification phase of PRA, the interdependency between a pair of events in expressed with the aid of the correlation coefficient. For the purpose of demonstrating the methodology, the data base used in the Accident Sequence Precursor Study (ASP) was adopted and simulated to obtain distributions for the correlation coefficients. A computer program entitled Correlation Coefficient Generator (CCG) was developed to generate a distribution for each correlation coefficient. The method of bootstrap technique was employed in the CCG computer code to determine confidence limits of the estimated correlation coefficients. A second computer program designated CORRELATE was also developed to obtain probability intervals for both fault trees and accident sequences with statistically correlated failure data
Mediterranean spotted fever and hearing impairment: a rare complication

Directory of Open Access Journals (Sweden)

Raffaella Rossio

2015-06-01

We describe a case of Rickettsia conorii that was complicated with hearing loss and did not respond to specific treatment. Hearing loss is a rare event, but clinicians should be aware of this complication.
Periodontitis in Chronic Heart Failure.

Science.gov (United States)

Fröhlich, Hanna; Herrmann, Kristina; Franke, Jennifer; Karimi, Alamara; Täger, Tobias; Cebola, Rita; Katus, Hugo A; Zugck, Christian; Frankenstein, Lutz

2016-08-01

Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases.
Total artificial heart implantation for biventricular failure due to eosinophilic myocarditis.

Science.gov (United States)

Kawabori, Masashi; Kurihara, Chitaru; Miller, Yair; Heck, Kent A; Bogaev, Roberta C; Civitello, Andrew B; Cohn, William E; Frazier, O H; Morgan, Jeffrey A

2017-09-01

Idiopathic hypereosinophilic syndrome is a condition of unknown etiology characterized by proliferation of eosinophils and their infiltration into tissues. Although cardiac involvement is rare, eosinophilic myocarditis can lead to life-threating fulminant congestive heart failure. Treatment of patients with eosinophilic myocarditis is challenging as heart failure can be caused by biventricular dysfunction. To our knowledge, this is the first case reported in the literature describing a patient with acute severe biventricular heart failure caused by eosinophilic myocarditis with mural left ventricular apical thrombus who was successfully treated with implantation of a total artificial heart as a bridge to heart transplant.
Severe renal failure in acute bacterial pyelonephritis: Do not forget corticosteroids

Directory of Open Access Journals (Sweden)

Sqalli Tarik

2010-01-01

Full Text Available Acute renal failure (ARF is a rare complication of acute pyelonephritis in adult immunocompetent patients. Recovery of renal function usually occurs if antibiotics are promptly initiated. However, long-term consequences of renal scarring due to acute pyelonephritis are probably underestimated, and some patients present with prolonged renal failure despite adequate antibiotic therapy. We report two cases of severe ARF complicating bacterial pyelonephritis successfully treated with corticosteroids in association with conventional antibiotics.
Effectiveness of infliximab after adalimumab failure in Crohn's disease.

Science.gov (United States)

Chaparro, María; Andreu, Montserrat; Barreiro-de Acosta, Manuel; García-Planella, Esther; Ricart, Elena; Domènech, Eugeni; Esteve, María; Merino, Olga; Nos, Pilar; Peñalva, Mireia; Gisbert, Javier P

2012-10-07

To evaluate the effectiveness of infliximab as a second-line therapy in Crohn's disease patients after adalimumab failure. A historical cohort study in a community-based gastroenterology practice evaluated Crohn's disease patients treated with infliximab (induction plus maintenance) after adalimumab failure. Patients were identified using a large Spanish database (ENEIDA). We included 15 Crohn's disease patients who received infliximab after adalimumab failure. Five patients discontinued adalimumab due to loss of response, 3 due to adverse events and 7 due to partial response. After infliximab therapy was started, all patients who had interrupted adalimumab due to loss of efficacy regained response. All patients who discontinued adalimumab due to adverse events responded to infliximab and maintained this response; one of these patients had an uneventful course on infliximab, but 2 developed adverse events. None of the 7 patients who interrupted adalimumab due to partial response reached remission with infliximab. Switching from adalimumab to infliximab may be useful in patients who develop adverse effects or loss of response, however, the benefit of infliximab in primary nonresponders was not established.

The Fourth Branchial Complex Anomaly: A Rare Clinical Entity

Directory of Open Access Journals (Sweden)

Alpen B. Patel

2011-01-01

Full Text Available Fourth branchial pouch anomalies are rare congenital disorders of the neck and are a consequence of abnormal development of the branchial apparatus during embryogenesis. Failure to appropriately recognize these anomalies may result in misdiagnosis, insufficient treatment, and continued recurrence. Here, we present an unique presentation of two cases, describe their diagnosis, clinical course, and management, and review the literature regarding these interesting anomalies.
Acute liver failure and acute kidney injury: Definitions, prognosis, and outcome

NARCIS (Netherlands)

Włodzimirow, K.A.

2013-01-01

The objective of this thesis was to investigate definitions, prognostic indicators and their association with adverse events, mainly mortality for acute liver failure (ALF), acute-on-chronic liver failure (ACLF) and acute kidney injury (AKI).
A human reliability analysis (HRA) method for identifying and assessing the error of commission (EOC) from a diagnosis failure

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Whan; Jung, Won Dea; Park, Jin Yun; Kang, Dae Il

2005-01-01

The study deals with a method for systematically identifying and assessing the EOC events that might be caused from a diagnosis failure or misdiagnosis of the expected events in accident scenarios of nuclear power plants. The method for EOC identification and assessment consists of three steps: analysis of the potential for a diagnosis failure (or misdiagnosis), identification of the EOC events from the diagnosis failure, quantitative assessment of the identified EOC events. As a tool for analysing a diagnosis failure, the MisDiagnosis Tree Analysis (MDTA) technique is proposed with the taxonomy of misdiagnosis causes. Also, the guidance on the identification of EOC events and the classification system and data are given for quantitiative assessment. As an applicaton of the proposed method, the EOCs identification and assessment for Younggwang 3 and 4 plants and their impact on the plant risk were performed. As the result, six events or event sequences were considered for diagnosis failures and about 20 new Human Failure Events (HFEs) involving EOCs were identified. According to the assessment of the risk impact of the identified HFEs, they increase the CDF by 11.4 % of the current CDF value, which corresponds to 10.2 % of the new CDF. The small loss of coolant accident (SLOCA) turned out to be a major contributor to the increase of CDF resulting in 9.2 % increaseof the current CDF.
Diencephalic syndrome: a rare cause of failure to thrive.

Science.gov (United States)

Tosur, Mustafa; Tomsa, Anca; Paul, David L

2017-07-06

Timely diagnosis of diencephalic syndrome is not often the case for patients presenting with failure to thrive (FTT) because of its rarity and lack of specific symptoms. Herein, we report two cases of diencephalic syndrome (2-year-old girl and 10-month-old boy) presenting with severe emaciation. Both patients had histories of poor weight gain for months despite having good appetites prior to diagnosis. Initial work-up did not reveal the diagnosis. Horizontal nystagmus was noted in both patients: by a neurologist in the first patient and by a family member in the second patient. MRI of the brain showed large suprasellar mass and pilocytic astrocytoma was confirmed by pathology in each case. The patients were started on appropriate chemotherapy with interval improvements in weight gain. These cases illustrate the importance of cranial imaging and consideration of diencephalic syndrome for children presenting with FTT despite normal or increased caloric intake. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
Letter report seismic shutdown system failure mode and effect analysis

International Nuclear Information System (INIS)

KECK, R.D.

1999-01-01

The Supply Ventilation System Seismic Shutdown ensures that the 234-52 building supply fans, the dry air process fans and vertical development calciner are shutdown following a seismic event. This evaluates the failure modes and determines the effects of the failure modes
A fuzzy-based reliability approach to evaluate basic events of fault tree analysis for nuclear power plant probabilistic safety assessment

International Nuclear Information System (INIS)

Purba, Julwan Hendry

2014-01-01

Highlights: • We propose a fuzzy-based reliability approach to evaluate basic event reliabilities. • It implements the concepts of failure possibilities and fuzzy sets. • Experts evaluate basic event failure possibilities using qualitative words. • Triangular fuzzy numbers mathematically represent qualitative failure possibilities. • It is a very good alternative for conventional reliability approach. - Abstract: Fault tree analysis has been widely utilized as a tool for nuclear power plant probabilistic safety assessment. This analysis can be completed only if all basic events of the system fault tree have their quantitative failure rates or failure probabilities. However, it is difficult to obtain those failure data due to insufficient data, environment changing or new components. This study proposes a fuzzy-based reliability approach to evaluate basic events of system fault trees whose failure precise probability distributions of their lifetime to failures are not available. It applies the concept of failure possibilities to qualitatively evaluate basic events and the concept of fuzzy sets to quantitatively represent the corresponding failure possibilities. To demonstrate the feasibility and the effectiveness of the proposed approach, the actual basic event failure probabilities collected from the operational experiences of the David–Besse design of the Babcock and Wilcox reactor protection system fault tree are used to benchmark the failure probabilities generated by the proposed approach. The results confirm that the proposed fuzzy-based reliability approach arises as a suitable alternative for the conventional probabilistic reliability approach when basic events do not have the corresponding quantitative historical failure data for determining their reliability characteristics. Hence, it overcomes the limitation of the conventional fault tree analysis for nuclear power plant probabilistic safety assessment
Comprehensive analysis of RET common and rare variants in a series of Spanish Hirschsprung patients confirms a synergistic effect of both kinds of events

Directory of Open Access Journals (Sweden)

Castaño Luis

2011-10-01

Full Text Available Abstract Background RET is the major gene associated to Hirschsprung disease (HSCR with differential contributions of its rare and common, coding and noncoding mutations to the multifactorial nature of this pathology. In the present study, we have performed a comprehensive study of our HSCR series evaluating the involvement of both RET rare variants (RVs and common variants (CVs in the context of the disease. Methods RET mutational screening was performed by dHPLC and direct sequencing for the identification of RVs. In addition Taqman technology was applied for the genotyping of 3 RET CVs previously associated to HSCR, including a variant lying in an enhancer domain within RET intron 1 (rs2435357. Statistical analyses were performed using the SPSS v.17.0 to analyze the distribution of the variants. Results Our results confirm the strongest association to HSCR for the "enhancer" variant, and demonstrate a significantly higher impact of it in male versus female patients. Integration of the RET RVs and CVs analysis showed that in 91.66% of cases with both kinds of mutational events, the enhancer allele is in trans with the allele bearing the RET RV. Conclusions A gender effect exists on both the transmission and distribution of rare coding and common HSCR causing mutations. In addition, these RET CVs and RVs seem to act in a synergistic way leading to HSCR phenotype.
49 CFR 214.529 - In-service failure of primary braking system.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false In-service failure of primary braking system. 214... Maintenance Machines and Hi-Rail Vehicles § 214.529 In-service failure of primary braking system. (a) In the event of a total in-service failure of its primary braking system, an on-track roadway maintenance...
Acute respiratory failure in 3 children with juvenile myelomonocytic leukemia

DEFF Research Database (Denmark)

Gustafsson, Britt; Hellebostad, Marit; Ifversen, Marianne

2011-01-01

Juvenile myelomonocytic leukemia is a rare hematopoietic stem cell disease in children with features of both myelodysplasia and myeloproliferation. Extramedullary involvement has been reported and pulmonary involvement secondary to leukemic infiltration is an initial manifestation, which may resu...... in acute respiratory failure....
Association of hypothyroidism with adverse events in patients with heart failure receiving cardiac resynchronization therapy.

Science.gov (United States)

Sharma, Ajay K; Vegh, Eszter; Orencole, Mary; Miller, Alexandra; Blendea, Dan; Moore, Stephanie; Lewis, Gregory D; Singh, Jagmeet P; Parks, Kimberly A; Heist, E Kevin

2015-05-01

Hypothyroidism is associated with an adverse prognosis in cardiac patients in general and in particular in patients with heart failure (HF). The aim of this study was to evaluate the impact of hypothyroidism on patients with HF receiving cardiac resynchronization therapy (CRT). Additionally, the impact of level of control of hypothyroidism on risk of adverse events after CRT implantation was also evaluated. We included consecutive patients in whom a CRT device was implanted from April 2004 to April 2010 at our institution with sufficient follow-up data available for analysis; 511 patients were included (age 68.5±12.4 years, women 20.4%); 84 patients with a clinical history of hypothyroidism, on treatment with thyroid hormone repletion or serum thyroid-stimulating hormone level≥5.00 μU/ml, were included in the hypothyroid group. The patients were followed for up to 3 years after implant for a composite end point of hospitalization for HF, left ventricular assist device placement, or heart transplant and cardiac death; 215 composite end point events were noted in this period. In a multivariate model, hypothyroidism (hazard ratio [HR] 1.46, 95% confidence interval [CI] 1.027 to 2.085, p=0.035), female gender (HR 0.64, 95% CI 0.428 to 0.963, p=0.032), and creatinine (HR 1.26, 95% CI 1.145 to 1.382, phypothyroidism at baseline developed the composite end point compared with 39.8% of those with euthyroidism (p=0.02). In conclusion, hypothyroidism is associated with a worse prognosis after CRT implantation. Copyright © 2015 Elsevier Inc. All rights reserved.
Ulcerative Uremic Stomatitis - Review of the Literature and A Rare Case Report

Directory of Open Access Journals (Sweden)

Shantala Arunkumar

2015-01-01

Full Text Available Uremic Stomatitis (US represents a comparatively uncommon intraoral complication seen, mostly, in cases of end-stage renal disease or undiagnosed or untreated chronic renal failure. Its frequency has diminished due to the advent of renal dialysis. Clinically uremic stomatitis is characterized by the presence of painful plaques and crusts that are usually distributed on the buccal and labial mucosa, dorsal or ventral surface of the tongue, gingiva, and floor of the mouth. Ultimate treatment consists of improvement of blood urea concentration and underlying renal failure is supported by enhancement of oral hygiene with antiseptic mouthwashes and antimicrobial/antifungal agents, if necessary. Here we report a rare case of ulcerative type of uremic stomatitis occurring in a patient of chronic renal failure due to sudden relapse of uremia and reviewed the possible pathophysiology of oral symptoms of chronic renal failure.
Failure Waves in Shock-Compressed Glasses

International Nuclear Information System (INIS)

Kanel, G. I.

2006-01-01

The failure wave is a network of cracks that are nucleated on the surface and propagate into the elastically stressed body. It is a mode of catastrophic fracture in an elastically stressed media whose relevance is not limited to impact events. In the paper, main properties of the failure waves are summarized and discussed. It has been shown that the failure wave is really a wave process which is characterized by small increase of the longitudinal stress and corresponding increments of the particle velocity and the density. The propagation velocity of the failure wave is less than the sound speed; it is not directly related to the compressibility but is determined by the crack growth speed. The failure wave is steady if the stress state ahead of it is supported unchanging. In some sense the process is similar to a subsonic combustion wave. Computer simulations based on the phenomenological combustion-like model reproduces well all kinematical aspects of the phenomenon
On a Stochastic Failure Model under Random Shocks

Science.gov (United States)

Cha, Ji Hwan

2013-02-01

In most conventional settings, the events caused by an external shock are initiated at the moments of its occurrence. In this paper, we study a new classes of shock model, where each shock from a nonhomogeneous Poisson processes can trigger a failure of a system not immediately, as in classical extreme shock models, but with delay of some random time. We derive the corresponding survival and failure rate functions. Furthermore, we study the limiting behaviour of the failure rate function where it is applicable.
Identification of radiopure titanium for the LZ dark matter experiment and future rare event searches

Science.gov (United States)

Akerib, D. S.; Akerlof, C. W.; Akimov, D. Yu.; Alsum, S. K.; Araújo, H. M.; Arnquist, I. J.; Arthurs, M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Balashov, S.; Barry, M. J.; Belle, J.; Beltrame, P.; Benson, T.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boast, K. E.; Bolozdynya, A.; Boxer, B.; Bramante, R.; Brás, P.; Buckley, J. H.; Bugaev, V. V.; Bunker, R.; Burdin, S.; Busenitz, J. K.; Carels, C.; Carlsmith, D. L.; Carlson, B.; Carmona-Benitez, M. C.; Chan, C.; Cherwinka, J. J.; Chiller, A. A.; Chiller, C.; Cottle, A.; Coughlen, R.; Craddock, W. W.; Currie, A.; Dahl, C. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edberg, T. K.; Edwards, W. R.; Emmet, W. T.; Faham, C. H.; Fiorucci, S.; Fruth, T.; Gaitskell, R. J.; Gantos, N. J.; Gehman, V. M.; Gerhard, R. M.; Ghag, C.; Gilchriese, M. G. D.; Gomber, B.; Hall, C. R.; Hans, S.; Hanzel, K.; Haselschwardt, S. J.; Hertel, S. A.; Hillbrand, S.; Hjemfelt, C.; Hoff, M. D.; Holbrook, B.; Holtom, E.; Hoppe, E. W.; Hor, J. Y.-K.; Horn, M.; Huang, D. Q.; Hurteau, T. W.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kaboth, A.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Khazov, A.; Khromov, A. V.; Konovalov, A. M.; Korolkova, E. V.; Koyuncu, M.; Kraus, H.; Krebs, H. J.; Kudryavtsev, V. A.; Kumpan, A. V.; Kyre, S.; Lee, C.; Lee, H. S.; Lee, J.; Leonard, D. S.; Leonard, R.; Lesko, K. T.; Levy, C.; Liao, F.-T.; Lin, J.; Lindote, A.; Linehan, R. E.; Lippincott, W. H.; Liu, X.; Lopes, M. I.; Lopez Paredes, B.; Lorenzon, W.; Luitz, S.; Majewski, P.; Manalaysay, A.; Manenti, L.; Mannino, R. L.; Markley, D. J.; Martin, T. J.; Marzioni, M. F.; McConnell, C. T.; McKinsey, D. N.; Mei, D.-M.; Meng, Y.; Miller, E. H.; Mizrachi, E.; Mock, J.; Monzani, M. E.; Morad, J. A.; Mount, B. J.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; Nikkel, J. A.; O'Dell, J.; O'Sullivan, K.; Olcina, I.; Olevitch, M. A.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Piepke, A.; Powell, S.; Preece, R. M.; Pushkin, K.; Ratcliff, B. N.; Reichenbacher, J.; Reichhart, L.; Rhyne, C. A.; Richards, A.; Rodrigues, J. P.; Rose, H. J.; Rosero, R.; Rossiter, P.; Saba, J. S.; Sarychev, M.; Schnee, R. W.; Schubnell, M.; Scovell, P. R.; Shaw, S.; Shutt, T. A.; Silva, C.; Skarpaas, K.; Skulski, W.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Sosnovtsev, V. V.; Stancu, I.; Stark, M. R.; Stephenson, S.; Stiegler, T. M.; Stifter, K.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Temples, D.; Terman, P. A.; Thomas, K. J.; Thomson, J. A.; Tiedt, D. R.; Timalsina, M.; To, W. H.; Tomás, A.; Tope, T. E.; Tripathi, M.; Tvrznikova, L.; Va'Vra, J.; Vacheret, A.; van der Grinten, M. G. D.; Verbus, J. R.; Vuosalo, C. O.; Waldron, W. L.; Wang, R.; Watson, R.; Webb, R. C.; Wei, W.-Z.; While, M.; White, D. T.; Whitis, T. J.; Wisniewski, W. J.; Witherell, M. S.; Wolfs, F. L. H.; Woodward, D.; Worm, S.; Xu, J.; Yeh, M.; Yin, J.; Zhang, C.; Lux-Zeplin (LZ) Collaboration

2017-11-01

The LUX-ZEPLIN (LZ) experiment will search for dark matter particle interactions with a detector containing a total of 10 tonnes of liquid xenon within a double-vessel cryostat. The large mass and proximity of the cryostat to the active detector volume demand the use of material with extremely low intrinsic radioactivity. We report on the radioassay campaign conducted to identify suitable metals, the determination of factors limiting radiopure production, and the selection of titanium for construction of the LZ cryostat and other detector components. This titanium has been measured with activities of 238Ue < 1.6 mBq/kg, 238Ul < 0.09 mBq/kg, 232The = 0.28 ± 0.03 mBq/kg, 232Thl = 0.25 ± 0.02 mBq/kg, 40K < 0.54 mBq/kg, and 60Co < 0.02 mBq/kg (68% CL). Such low intrinsic activities, which are some of the lowest ever reported for titanium, enable its use for future dark matter and other rare event searches. Monte Carlo simulations have been performed to assess the expected background contribution from the LZ cryostat with this radioactivity. In 1,000 days of WIMP search exposure of a 5.6-tonne fiducial mass, the cryostat will contribute only a mean background of 0.160 ± 0.001(stat) ± 0.030(sys) counts.
Signal analysis for failure detection

International Nuclear Information System (INIS)

Parpaglione, M.C.; Perez, L.V.; Rubio, D.A.; Czibener, D.; D'Attellis, C.E.; Brudny, P.I.; Ruzzante, J.E.

1994-01-01

Several methods for analysis of acoustic emission signals are presented. They are mainly oriented to detection of changes in noisy signals and characterization of higher amplitude discrete pulses or bursts. The aim was to relate changes and events with failure, crack or wear in materials, being the final goal to obtain automatic means of detecting such changes and/or events. Performance evaluation was made using both simulated and laboratory test signals. The methods being presented are the following: 1. Application of the Hopfield Neural Network (NN) model for classifying faults in pipes and detecting wear of a bearing. 2. Application of the Kohonnen and Back Propagation Neural Network model for the same problem. 3. Application of Kalman filtering to determine time occurrence of bursts. 4. Application of a bank of Kalman filters (KF) for failure detection in pipes. 5. Study of amplitude distribution of signals for detecting changes in their shape. 6. Application of the entropy distance to measure differences between signals. (author). 10 refs, 11 figs
Snow fracture: From micro-cracking to global failure

Science.gov (United States)

Capelli, Achille; Reiweger, Ingrid; Schweizer, Jürg

2017-04-01

Slab avalanches are caused by a crack forming and propagating in a weak layer within the snow cover, which eventually causes the detachment of the overlying cohesive slab. The gradual damage process leading to the nucleation of the initial failure is still not entirely understood. Therefore, we studied the damage process preceding snow failure by analyzing the acoustic emissions (AE) generated by bond failure or micro-cracking. The AE allow studying the ongoing progressive failure in a non-destructive way. We performed fully load-controlled failure experiments on snow samples presenting a weak layer and recorded the generated AE. The size and frequency of the generated AE increased before failure revealing an acceleration of the damage process with increased size and frequency of damage and/or microscopic cracks. The AE energy was power-law distributed and the exponent (b-value) decreased approaching failure. The waiting time followed an exponential distribution with increasing exponential coefficient λ before failure. The decrease of the b-value and the increase of λ correspond to a change in the event distribution statistics indicating a transition from homogeneously distributed uncorrelated damage producing mostly small AE to localized damage, which cause larger correlated events which leads to brittle failure. We observed brittle failure for the fast experiment and a more ductile behavior for the slow experiments. This rate dependence was reflected also in the AE signature. In the slow experiments the b value and λ were almost constant, and the energy rate increase was moderate indicating that the damage process was in a stable state - suggesting the damage and healing processes to be balanced. On a shorter time scale, however, the AE parameters varied indicating that the damage process was not steady but consisted of a sum of small bursts. We assume that the bursts may have been generated by cascades of correlated micro-cracks caused by localization of
Aldosterone, mortality, and acute ischaemic events in coronary artery disease patients outside the setting of acute myocardial infarction or heart failure.

Science.gov (United States)

Ivanes, Fabrice; Susen, Sophie; Mouquet, Frédéric; Pigny, Pascal; Cuilleret, François; Sautière, Karine; Collet, Jean-Philippe; Beygui, Farzin; Hennache, Bernadette; Ennezat, Pierre Vladimir; Juthier, Françis; Richard, Florence; Dallongeville, Jean; Hillaert, Marieke A; Doevendans, Pieter A; Jude, Brigitte; Bertrand, Michel; Montalescot, Gilles; Van Belle, Eric

2012-01-01

Recent studies have demonstrated that aldosterone levels measured in patients with heart failure or acute myocardial infarction (MI) are associated with long-term mortality, but the association with aldosterone levels in patients with coronary artery disease (CAD) outside these specific settings remains unknown. In addition, no clear mechanism has been elucidated to explain these observations. The present study was designed to evaluate the relationship between the level of aldosterone and the risk of death and acute ischaemic events in CAD patients with a preserved left ventricular (LV) function and no acute MI. In 799 consecutive CAD patients referred for elective coronary angioplasty measurements were obtained before the procedure for: aldosterone (median = 25 pg/mL), brain natriuretic peptide (BNP) (median = 35 pg/mL), hsC-reactive protein (median = 4.17 mg/L), and left ventricular ejection fraction (mean = 58%). Patients with acute MI or coronary syndrome (ACS) who required urgent revascularization were not included in the study. The primary endpoint, cardiovascular death, occurred in 41 patients during a median follow-up period of 14.9 months. Secondary endpoints-total mortality, acute ischaemic events (acute MI or ischaemic stroke), and the composite of death and acute ischaemic events-were observed in 52, 54, and 94 patients, respectively. Plasma aldosterone was found to be related to BMI, hypertension and NYHA class, and inversely related to age, creatinine clearance, and use of beta-blockers. Multivariate Cox model analysis demonstrated that aldosterone was independently associated with cardiovascular mortality (P = 0.001), total mortality (P = 0.001), acute ischaemic events (P = 0.01), and the composite of death and acute ischaemic events (P = 0.004). Reclassification analysis, using integrated discrimination improvement (IDI) and net reclassification improvement (NRI), demonstrated incremental predictive value of aldosterone (P acute MI, the level of
Reliability analysis of multi-trigger binary systems subject to competing failures

International Nuclear Information System (INIS)

Wang, Chaonan; Xing, Liudong; Levitin, Gregory

2013-01-01

This paper suggests two combinatorial algorithms for the reliability analysis of multi-trigger binary systems subject to competing failure propagation and failure isolation effects. Propagated failure with global effect (PFGE) is referred to as a failure that not only causes outage to the component from which the failure originates, but also propagates through all other system components causing the entire system failure. However, the propagation effect from the PFGE can be isolated in systems with functional dependence (FDEP) behavior. This paper studies two distinct consequences of PFGE resulting from a competition in the time domain between the failure isolation and failure propagation effects. As compared to existing works on competing failures that are limited to systems with a single FDEP group, this paper considers more complicated cases where the systems have multiple dependent FDEP groups. Analysis of such systems is more challenging because both the occurrence order between the trigger failure event and PFGE from the dependent components and the occurrence order among the multiple trigger failure events have to be considered. Two combinatorial and analytical algorithms are proposed. Both of them have no limitation on the type of time-to-failure distributions for the system components. Their correctness is verified using a Markov-based method. An example of memory systems is analyzed to demonstrate and compare the applications and advantages of the two proposed algorithms. - Highlights: ► Reliability of binary systems with multiple dependent functional dependence groups is analyzed. ► Competing failure propagation and failure isolation effect is considered. ► The proposed algorithms are combinatorial and applicable to any arbitrary type of time-to-failure distributions for system components.
Tumoral calcinosis in a dog with chronic renal failure

International Nuclear Information System (INIS)

Spotswood, T.C.

2003-01-01

A 2-year-old male German shepherd dog in poor bodily condition was evaluated for thoracic limb lameness due to a large, firm mass medial to the left cranial scapula. Radiography revealed several large cauliflower-like mineralized masses in the craniomedial left scapula musculature, pectoral region and bilaterally in the biceps tendon sheaths. Urinalysis, haematology and serum biochemistry showed that the dog was severely anaemic, hyperphosphataemic and in chronic renal failure. The dog was euthanased and a full post mortem performed. A diagnosis of chronic renal failure with secondary hyperparathyroidism was confirmed. The mineralised masses were grossly and histopathologically consistent with a diagnosis of tumoral calcinosis. Tumoral calcinosis associated with chronic renal failure that does not involve the foot pads is rarely seen
Loss of preferred power events in German BWRs and PWRs

International Nuclear Information System (INIS)

Frisch, W.

1984-01-01

This chapter examines the variety of courses which the loss of auxiliary power case may take in different plants, depending on the initiation of the event, the switching to the alternate auxiliary power supply and the automatic start-up sequences of auxiliaries (e.g. feedwater pumps, condensate pumps) after a short term interruption of auxiliary power. Topics considered include main station transformer failure in a boiling water reactor (BWR), main plant features, event description, evaluation of the event, deviations from expected behavior, operator actions, a comparison with start-up tests and other events, a comparison with postcalculations, and auxiliary transformer failure in a pressurized water reactor (PWR). Loss of preferred (or auxiliary) power events are standard design cases taken into account in the design of many reactor and plant systems

Fuel failure detection in operating reactors

International Nuclear Information System (INIS)

Seigel, B.; Hagen, H.H.

1977-12-01

Activity detectors in commercial BWRs and PWRs are examined to determine their capability to detect a small number of fuel rod failures during reactor operation. The off-gas system radiation monitor in a BWR and the letdown line radiation monitor in a PWR are calculated to have this capability, and events are cited that support this analysis. Other common detectors are found to be insensitive to small numbers of fuel failures. While adequate detectors exist for normal and transient operation, those detectors would not perform rapidly enough to be useful during accidents; in most accidents, however, primary system sensors (pressure, temperature, level) would provide adequate warning. Advanced methods of fuel failure detection are mentioned
Fatal methemoglobinemia complicating alkaptonuria (ochronosis): a rare presentation.

Science.gov (United States)

Freeman, Amanda R; Wills, Stephen M

2018-06-01

A 61-year-old female died in hospital with multiple organ failure 4 weeks following presentation with acute kidney injury, hemolytic anemia and methemoglobinemia. At autopsy, brown to black discoloration of cartilages was observed. Histology revealed brown pigmentation of the hyaline cartilage, with focal full-thickness erosion of the articular hyaline cartilage, characteristic of alkaptonuria (ochronosis). Although alkaptonuria is rarely fatal, this case illustrates a rare acute fatal complication. Accumulation of circulating homgentisic acid secondary to acute derangement of renal function is believed to have overwhelmed the endogenous antioxidant processes, resulting in hemolysis and methemoglobinemia, which were refractory to treatment. Small numbers of cases have previously been reported in the literature in patients known to suffer with the disease, all of which were preceded by acute kidney injury. Whilst the clinical diagnosis of alkaptonuria may be challenging, the autopsy findings of this rare condition are striking and this case illustrates the utility of the autopsy, albeit retrospectively, in arriving at a diagnosis. To our knowledge this is the first reported case where previously undiagnosed alkaptonuria has presented with methemoglobinemia.
New PHOBOS results on event-by-event fluctuations

Science.gov (United States)

Alver, B.; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Harnarine, I.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Reed, C.; Remsberg, L. P.; Reuter, M.; Richardson, E.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Szostak, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Willhelm, D.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wyngaardt, S.; Wysłouch, B.

2006-04-01

We present new results from the PHOBOS experiment at RHIC on event-by-event fluctuations of particle multiplicities and angular distributions in nucleus-nucleus collisions at RHIC. Our data for Au+Au collisions at √sNN = 200 GeV show that at a level of 10-4 or less, no rare, large-amplitude fluctuations in the total multiplicity distributions or the shape of the pseudorapidity distributions are observed. We however find significant short-range multiplicity correlations in these data, that can be described as particle production in clusters. In Cu+Cu collisions, we observe large final-state azimuthal anisotropies ν2. A common scaling behavior for Cu+Cu and Au+Au for these anisotropies emerges when fluctuations in the initial state geometry are taken into account.
Leveraging Failure in Design Research

Science.gov (United States)

Lobato, Joanne; Walters, C. David; Hohensee, Charles; Gruver, John; Diamond, Jaime Marie

2015-01-01

Even in the resource-rich, more ideal conditions of many design-based classroom interventions, unexpected events can lead to disappointing results in student learning. However, if later iterations in a design research study are more successful, the previous failures can provide opportunities for comparisons to reveal subtle differences in…
Acute pancreatitis and acute renal failure following multiple hornet stings

Directory of Open Access Journals (Sweden)

N. Sharma

2006-04-01

Full Text Available Hymenoptera is a class of insects that sting in order to subdue their prey. Humans coming into accidental contact with these insects results in stings that may cause from mild local reaction like weal formation around the sting site to severe systemic reactions such as intravascular hemolysis, acute renal failure, pulmonary edema, cerebral edema, and rarely pancreatitis. We report here the clinical course of a patient who developed concurrent acute pancreatitis and pigment-induced acute renal failure after multiple hornet stings.
Co-occurrence of intraoral hemangioma and port wine stain: A rare case

Directory of Open Access Journals (Sweden)

Prasanna Kumar Rao

2012-01-01

Full Text Available Hemangiomas are neoplastic proliferations of endothelial cells, characterized by a period of growth after birth, and eventual spontaneous involution. The course can be uneventful with spontaneous resolution; or it may be marked by complications such as infection, bleeding, ulceration, visual defects and feeding difficulties. Apart from these, rare life-threatening complications such as congestive heart failure and consumption coagulopathy may also be seen. Although hemangiomas commonly occur in the head and neck region, intraoral occurrence is relatively rare. A port wine stain is defined as a macular telangiectatic patch which is present at birth and remains throughout life. They may be localized or extensive, affecting a whole limb. This article reports a rare case of co-occurrence of port wine stain with intraoral hemangioma.
Identification of failure type in corroded pipelines: a bayesian probabilistic approach.

Science.gov (United States)

Breton, T; Sanchez-Gheno, J C; Alamilla, J L; Alvarez-Ramirez, J

2010-07-15

Spillover of hazardous materials from transport pipelines can lead to catastrophic events with serious and dangerous environmental impact, potential fire events and human fatalities. The problem is more serious for large pipelines when the construction material is under environmental corrosion conditions, as in the petroleum and gas industries. In this way, predictive models can provide a suitable framework for risk evaluation, maintenance policies and substitution procedure design that should be oriented to reduce increased hazards. This work proposes a bayesian probabilistic approach to identify and predict the type of failure (leakage or rupture) for steel pipelines under realistic corroding conditions. In the first step of the modeling process, the mechanical performance of the pipe is considered for establishing conditions under which either leakage or rupture failure can occur. In the second step, experimental burst tests are used to introduce a mean probabilistic boundary defining a region where the type of failure is uncertain. In the boundary vicinity, the failure discrimination is carried out with a probabilistic model where the events are considered as random variables. In turn, the model parameters are estimated with available experimental data and contrasted with a real catastrophic event, showing good discrimination capacity. The results are discussed in terms of policies oriented to inspection and maintenance of large-size pipelines in the oil and gas industry. 2010 Elsevier B.V. All rights reserved.
Bifid mandibular canal: a rare or underestimated entity?

Directory of Open Access Journals (Sweden)

Ibrahim Nasseh

2016-10-01

Full Text Available One of the rare anatomical variations that can be of significant importance for the dentist is the bifid mandibular canal. Many complications can occur from this condition such as failure of anesthesia when performing inferior alveolar nerve block, difficulties during the surgical extraction of the third mandibular molar, and during implants placement. Therefore, good knowledge of this condition is essential. In this report, we describe the radiographic finding of a unilateral bifid mandibular canal.
Fulminant Hepatic Failure Secondary to Primary Hepatic Angiosarcoma

Directory of Open Access Journals (Sweden)

Ayokunle T. Abegunde

2015-01-01

Full Text Available Background. Hepatic angiosarcoma is a rare and aggressive tumor that often presents at an advanced stage with nonspecific symptoms. Objective. To report a case of primary hepatic angiosarcoma in an otherwise healthy man with normal liver function tests two months prior to presenting with a short period of jaundice that progressed to fulminant hepatic failure. Methods. Case report and review of literature. Conclusion. This case illustrates the rapidity of progression to death after the onset of symptoms in a patient with hepatic angiosarcoma. Research on early diagnostic strategies and newer therapies are needed to improve prognosis in this rare and poorly understood malignancy with limited treatment options.
Operating experience feedback report: Service water system failures and degradations: Volume 3

International Nuclear Information System (INIS)

Lam, P.; Leeds, E.

1988-11-01

A comprehensive review and evaluation of service water system failures and degradations observed in operating events in light water reactors from 1980 to 1987 has been conducted. The review and evaluation focused on the identification of causes of system failures and degradations, the adequacy of corrective actions implemented and planned, and the safety significance of the operating events. The results of this review and evaluation indicate that the service water system failures and degradations have significant safety implications. These system failures and degradations are attributable to a great variety of causes, and have adverse impact on a large number of safety-related systems and components which are required to mitigate reactor accidents. Specifically, the causes of failures and degradations include various fouling mechanisms (sediment deposition, biofouling, corrosion and erosion, pipe coating failure, calcium carbonate, foreign material and debris intrusion); single failures and other design deficiencies; flooding; multiple equipment failures; personnel and procedural errors; and seismic deficiencies. Systems and components adversely impacted by a service water system failure or degradation include the component cooling water system, emergency diesel generators, emergency core cooling system pumps and heat exchangers, the residual heat removal system, containment spray and fan coolers, control room chillers, and reactor building cooling units. 44 refs., 10 figs., 5 tabs
A rare case of acute poster ior reversible encephalopathy syndrome involving brainstem in a child

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Olfa Chakroun-Walha

2016-11-01

Full Text Available Posterior reversible encephalopathy syndrome (PRES is a rare entity involving brainstem in very rare reported cases. We describe here the case of a boy who presented to the emergency department for headaches and strabismus. Diagnosis of PRES was retained by magnetic resonance imaging. The causes were blood pressure urgency and renal failure. Location of lesions was very rarely reported in literature and neurological troubles were persistent. Emergency physicians should evocate PRES each time there is a clinical context associated with neurological troubles by a normal brain CT scan. Early diagnosis is very important to treat its causes and improve prognosis.
Multivariable analysis of a failure event of pressure regulator in a BWR; Analisis multivariable de un evento de falla del regulador de presion en un BWR

Energy Technology Data Exchange (ETDEWEB)

Castillo D, R.; Ortiz V, J. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Calleros M, G. [Comision Federal de Electricidad, Central Nucleoelectrica Laguna Verde, Carretera Cardel-Nautla, Km. 43.5, Veracruz (Mexico)], e-mail: rogelio.castillo@inin.gob.mx

2009-10-15

The boiling water reactors can experiment three types of instabilities: one caused by the controllers failure of plant, another renowned instability by reactivity and the last knew as thermal hydraulics instability. An event of pressure regulator failure of electro-hydraulic control of Unit 1 of nuclear power plant of Laguna Verde was analyzed, which caused power oscillations that were increasing their magnitude in the time course. The event has been analyzed using the Fourier transformation in short time for time-frequency analysis and for the frequency domain be employment the power spectral density. Both techniques reported a resonance to oscillation frequency of 0.055 Hz in the power spectrum, this frequency is of observed order of magnitude when fail the reactor control systems. However, these analysis did not allow to study the interrelation of event signals. Of the previous studies, were obtained power spectral densities containing picks and valleys related with the dynamic behaviour of reactor, which includes the control systems performance. For a pick or present valley to a specific frequency in the power spectrum for one of previous variables, can determine the influence of other variables on the pick or valley by relative contribution of power. This method was established in a developed program of name Noise, which uses a multivariable autoregressive model to obtain the autoregressive coefficients, and starting from them the relative contribution of power is determined. Basically two important results were obtained, the first is related with the influence of feed water flow on the other variables to the frequency of 0.055 Hz, the second is related with the instability by reactivity and confirms that this way was not excited during the event. (Author)
Isotropic events observed with a borehole array in the Chelungpu fault zone, Taiwan.

Science.gov (United States)

Ma, Kuo-Fong; Lin, Yen-Yu; Lee, Shiann-Jong; Mori, Jim; Brodsky, Emily E

2012-07-27

Shear failure is the dominant mode of earthquake-causing rock failure along faults. High fluid pressure can also potentially induce rock failure by opening cavities and cracks, but an active example of this process has not been directly observed in a fault zone. Using borehole array data collected along the low-stress Chelungpu fault zone, Taiwan, we observed several small seismic events (I-type events) in a fluid-rich permeable zone directly below the impermeable slip zone of the 1999 moment magnitude 7.6 Chi-Chi earthquake. Modeling of the events suggests an isotropic, nonshear source mechanism likely associated with natural hydraulic fractures. These seismic events may be associated with the formation of veins and other fluid features often observed in rocks surrounding fault zones and may be similar to artificially induced hydraulic fracturing.
Adult-onset nemaline myopathy presenting as respiratory failure.

LENUS (Irish Health Repository)

Kelly, Emer

2008-11-01

Nemaline myopathy is a rare congenital myopathy that generally presents in childhood. We report a case of a 44-year-old man who presented with severe hypoxic hypercapnic respiratory failure as the initial manifestation of nemaline myopathy. After starting noninvasive ventilation, his pulmonary function test results improved substantially, and over the 4 years since diagnosis his respiratory function remained stable. There are few reported cases of respiratory failure in patients with adult-onset nemaline myopathy, and the insidious onset in this case is even more unusual. This case highlights the varied presenting features of adult-onset nemaline myopathy and that noninvasive ventilation improves respiratory function.
Case of congestive heart failure induced by therapeutic irradiation

Energy Technology Data Exchange (ETDEWEB)

Kushigami, Motohiko; Suruda, Hidetoshi; Mizukoshi, Masato; Umemoto, Masaaki; Fujiwara, Setsuko; Yamamoto, Katsuhiro; Ueno, Yuji; Nishio, Ichiro; Masuyama, Yoshiaki

1985-02-01

Valvular insufficiency in radiation-induced heart disease is very rare. We described a patient, 53 years old woman, who developed congestive heart failure 2.5 years later following radiotherapy for esophageal carcinoma. The findings on examinations including cardiac catheterization revealed pericarditis with effusion, mitral and tricuspid valve insufficiency and pulmonary infarction. (author).
Acute Renal Failure Following the Saharan Horned Viper (Cerastes ...

African Journals Online (AJOL)

Introduction: The Saharan horned viper (Cerastes cerastes) is a common snake in the sandy and rocky regions in the south of Morocco. Although nearly all snakes with medical relevance can induce acute renal failure (ARF), it's unusual except with bites by some viper species. ARF has very rarely been reported following ...
FRAC (failure rate analysis code): a computer program for analysis of variance of failure rates. An application user's guide

International Nuclear Information System (INIS)

Martz, H.F.; Beckman, R.J.; McInteer, C.R.

1982-03-01

Probabilistic risk assessments (PRAs) require estimates of the failure rates of various components whose failure modes appear in the event and fault trees used to quantify accident sequences. Several reliability data bases have been designed for use in providing the necessary reliability data to be used in constructing these estimates. In the nuclear industry, the Nuclear Plant Reliability Data System (NPRDS) and the In-Plant Reliability Data System (IRPDS), among others, were designed for this purpose. An important characteristic of such data bases is the selection and identification of numerous factors used to classify each component that is reported and the subsequent failures of each component. However, the presence of such factors often complicates the analysis of reliability data in the sense that it is inappropriate to group (that is, pool) data for those combinations of factors that yield significantly different failure rate values. These types of data can be analyzed by analysis of variance. FRAC (Failure Rate Analysis Code) is a computer code that performs an analysis of variance of failure rates. In addition, FRAC provides failure rate estimates
Failures and suggestions in Earthquake forecasting and prediction

Science.gov (United States)

Sacks, S. I.

2013-12-01

Seismologists have had poor success in earthquake prediction. However, wide ranging observations from earlier great earthquakes show that precursory data can exist. In particular, two aspects seem promising. In agreement with simple physical modeling, b-values decrease in highly loaded fault zones for years before failure. Potentially more usefully, in high stress regions, breakdown of dilatant patches leading to failure can yield expelled water-related observations. The volume increase (dilatancy) caused by high shear stresses decreases the pore pressure. Eventually, water flows back in restoring the pore pressure, promoting failure and expelling the extra water. Of course, in a generally stressed region there may be many small patches that fail, such as observed before the 1975 Haicheng earthquake. Only a few days before the major event will most of the dilatancy breakdown occur in the fault zone itself such as for the Tangshan, 1976 destructive event. Observations of 'water release' effects have been observed before the 1923 great Kanto earthquake, the 1984 Yamasaki event, the 1975 Haicheng and the 1976 Tangshan earthquakes and also the 1995 Kobe earthquake. While there are obvious difficulties in water release observations, not least because there is currently no observational network anywhere, historical data does suggest some promise if we broaden our approach to this difficult subject.
NRC concerns about steam generator tube U-bend failures

International Nuclear Information System (INIS)

Dillon, R.L.

1981-01-01

This paper concerns itself with genralized NRC regulatory policy regarding SGT failures and staff reports and opinions which may tend to influence the developing policy specific to U-bend failures. The most significant analysis at hand in predicting NRC policy on SGT U-bend failures is Marsh's Evaluation of Steam Generator Tube Rupture Events. Marsh sets out to describe and analyze the five steam generator tube ruptures that are known to NRC. All have occurred in the period 1975 to 1980
Essential thrombocythemia: a rare disease in childhood

Directory of Open Access Journals (Sweden)

Julia Maimone Beatrice

2013-01-01

Full Text Available Essential thrombocythemia is an acquired myeloproliferative disorder characterized by the proliferation of megakaryocytes in bone marrow, leading to a persistent increase in the number of circulating platelets and thus increasing the risk for thrombotic and hemorrhagic events. The disease features leukocytosis, splenomegaly, vascular occlusive events, hemorrhages and vasomotor disorders. The intricate mechanisms underlying the molecular pathogenesis of this disorder are not completely understood and are still a matter of discussion. Essential thrombocythemia is an extremely rare disorder during childhood. We report on a case of essential thrombocythemia in a child and discuss the diagnostic approach and treatment strategy.

ICDE project report on collection and analysis of common-cause failures of centrifugal pumps

International Nuclear Information System (INIS)

2000-01-01

Several member countries of OECD/NEA decided to establish the International Common-Cause Failure Data Exchange (ICDE) Project to encourage multilateral co-operation in the collection and analysis of data relating to Common-Cause Failure (CCF) events. The project was initiated in August 1994 in Sweden and was discussed at meetings in both Sweden and France in 1995. A coding benchmark exercise was defined which was evaluated at meetings held in Germany and in the US in 1996. Subsequently, the exchange of centrifugal pump data was defined; the first phase of this exchange was evaluated at meetings in Switzerland and in France in 1997. The objectives of the ICDE Project are: - to collect and analyse CCF events in the long term so as to better understand such events, their causes, and their prevention, - to generate qualitative insights into the root causes of CCF events which can then be used to derive approaches or mechanisms for their prevention or for mitigating their consequences, - to establish a mechanism for the efficient feedback of experience gained on CCF phenomena, including the development of defences against their occurrence, such as indicators for risk based inspections. The ICDE Project is envisaged as including all possible events of interest, comprising complete, partial and incipient CCF events, called 'ICDE events' in the following. The Project covers the key components of the main safety systems, like centrifugal pumps, diesel generators, motor operated valves, power operated relief valves, safety relief valves, check valves, RPS circuit breakers, batteries and transmitters. Data are collected in an MS ACCESS based databank implemented and maintained at ES-Konsult, Sweden, by NEA appointed clearinghouse. The databank is regularly updated. The clearinghouse and the project group operate it. In the modelling of common-cause failures in systems consisting of several redundant components, two kinds of events are distinguished: a) Unavailability of a
Common cause failures - a dilemma in perspective

International Nuclear Information System (INIS)

Smith, A.M.; Watson, I.A.

1980-01-01

This paper identifies the broad spectrum of common cause failure (CCF) definitions used by various authors. These definitions, as applied to real aircraft and nuclear reactor failure events, lead to a divergence of interpretation and a resultant confusion that obscures meaningful progress in CCF analysis. A new definition is proposed, explained, and tested against the examples. Technical as well as administrative practices are cited as ways to control or eliminate the product defects that lead to CCF. (author)
A periodic inspection and replacement policy for systems subject to competing failure modes due to degradation and traumatic events

Energy Technology Data Exchange (ETDEWEB)

Huynh, K.T., E-mail: tuan.huynh@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Barros, A., E-mail: anne.barros@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Castro, I.T., E-mail: inmatorres@unex.e [Departamento de Matematicas, Escuela Politecnica, 10071 Caceres (Spain)

2011-04-15

This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.
A periodic inspection and replacement policy for systems subject to competing failure modes due to degradation and traumatic events

International Nuclear Information System (INIS)

Huynh, K.T.; Barros, A.; Berenguer, C.; Castro, I.T.

2011-01-01

This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.
Renal failure in patients with multiple myeloma.

Science.gov (United States)

Almueilo, Samir H

2015-01-01

Renal dysfunction is encountered in 20-25% of patients with multiple myeloma (MM) at the time of diagnosis. There is often a precipitating event. Several biochemical and clinical correlations with renal failure in MM have been reported. Renal failure in MM is associated with worse outcome of the disease. We retrospectively analyzed the medical records of 64 patients with MM admitted to our institution during the period January 1992 to December 2012. Abnormal renal function was observed in 24 (37.5%) patients and 17 (26.6%) of them had renal failure; 14 of the 17 (82.4%) of patients with renal failure had Stage III MM. Urine Bence- Jones protein was positive in ten (58.8%) patients with renal failure versus ten (21.3%) patients without renal failure (P = 0.004). Potential precipitating factors of renal failure were determined in nine patients. Renal function normalized in 11 patients with simple measures, while six patients required hemodialysis; one remained dialysis dependent till time of death. Early mortality occurred in five (29.4%) patients with renal failure as compared with two (4.3%) patients in the group without renal failure (P = 0.005). In conclusion, renal failure is associated with a higher tumor burden and Bence-Jones proteinuria in patients with MM. It is reversible in the majority of patients; however, early mortality tends to be higher in patients with persistent renal failure.
The China Patient-centered Evaluative Assessment of Cardiac Events (China PEACE) retrospective heart failure study design.

Science.gov (United States)

Yu, Yuan; Zhang, Hongzhao; Li, Xi; Lu, Yuan; Masoudi, Frederick A; Krumholz, Harlan M; Li, Jing

2018-05-10

Heart failure (HF) is a leading cause of hospitalisation in China, which is experiencing a rapid increase in cardiovascular disease prevalence. Yet, little is known about current burden of disease, quality of care and treatment outcomes of HF in China. The objective of this paper is to describe the study methodology, data collection and abstraction, and progress to date of the China Patient-centered Evaluative Assessment of Cardiac Events 5 Retrospective Heart Failure Study (China PEACE 5r-HF). The China PEACE 5r-HF Study will examine a nationally representative sample of more than 10 000 patient records hospitalised for HF in 2015 in China. The study is a retrospective cohort study. Patients have been selected using a two-stage sampling design stratified by economic-geographical regions. We will collect patient characteristics, diagnostic testing, treatments and in-hospital outcomes, including death and complications, and charges of hospitalisation. Data quality will be monitored by a central coordinating centre and will address case ascertainment, data abstraction and data management. As of October 2017, we have sampled 15 538 medical records from 189 hospitals, and have received 15 057 (96.9%) of these for data collection, and completed data abstraction and quality control on 7971. The Central Ethics Committee at the Chinese National Center for Cardiovascular Diseases approved the study. All collaborating hospitals accepted central ethics committee approval with the exception of 15 hospitals, which obtained local approval by internal ethics committees. Findings will be disseminated in future peer-reviewed papers and will serve as a foundation for improving the care for HF in China. NCT02877914. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
A time-dependent event tree technique for modelling recovery operations

International Nuclear Information System (INIS)

Kohut, P.; Fitzpatrick, R.

1991-01-01

The development of a simplified time dependent event tree methodology is presented. The technique is especially applicable to describe recovery operations in nuclear reactor accident scenarios initiated by support system failures. The event tree logic is constructed using time dependent top events combined with a damage function that contains information about the final state time behavior of the reactor core. Both the failure and the success states may be utilized for the analysis. The method is illustrated by modeling the loss of service water function with special emphasis on the RCP [reactor coolant pump] seal LOCA [loss of coolant accident] scenario. 5 refs., 2 figs., 2 tabs
Valvular Heart Disease in Heart Failure

Directory of Open Access Journals (Sweden)

Giuseppe MC Rosano

2017-01-01

Full Text Available Structural valvular heart disease may be the cause of heart failure or may worsen the clinical status of patients with heart failure. Heart failure may also develop in patients treated with valve surgery. Patients with heart failure with valvular heart disease are at increased risk of events including sudden cardiac death. Before considering intervention (surgical or percutaneous all patients should receive appropriate medical and device therapy taking into account that vasodilators must be used with caution in patients with severe aortic stenosis. Numerous percutaneous and/or hybrid procedures have been introduced in the past few years and they are changing the management of valvular heart disease. In patients with heart failure and valvular heart disease, either primary or functional, the whole process of decision-making should be staged through a comprehensive evaluation of the risk– benefit ratio of different treatment strategies and should be made by a multidisciplinary ‘heart team’ with a particular expertise in valvular heart disease. The heart team should include heart failure cardiologists, cardiac surgeons/structural valve interventionists, imaging specialists, anaesthetists, geriatricians and intensive care specialists. This article will review recent developments and distill practical guidance in the management of this important heart failure co-morbidity.
MSA Mimic? Rare Occurrence of Anti-Hu Autonomic Failure and Thymoma in a Patient with Parkinsonism: Case Report and Literature Review

Directory of Open Access Journals (Sweden)

Vito A. G. Ricigliano

2018-01-01

Full Text Available Thymoma is a tumor originating from thymic gland, frequently manifesting with paraneoplastic neurological disorders. Its association with paraneoplastic dysautonomia is relatively uncommon. Here, we describe the challenging case of a 71 year-old female who developed subacute autonomic failure with digestive pseudo-obstruction, dysphagia, urinary tract dysfunction and orthostatic hypotension complicating an underlying extrapyramidal syndrome that had started 3 months before hospital admission. Autonomic symptoms had 2-month course and acutely worsened just before and during hospitalization. Combination of severe dysautonomia and parkinsonism mimicked rapidly progressing multiple system atrophy. However, diagnostic exams showed thymic tumor with positive anti-Hu antibodies on both serum and cerebrospinal fluid. Complete response of dysautonomia to immunoglobulins followed by thymectomy confirmed the diagnosis of anti-Hu-related paraneoplastic neurological syndrome. With regards to extrapyramidal symptoms, despite previous descriptions of paraneoplastic parkinsonism caused by other antineuronal antibodies, in our case no relation between anti-Hu and parkinsonism could be identified. A literature review of published reports describing anti-Hu positivity in thymic neoplasms highlighted that a definite autonomic disease due to anti-Hu antibodies is extremely rare in patients with thymoma but without myasthenia gravis, with only one case published so far.
HEDL empirical correlation of fuel pin top failure thresholds, status 1976

International Nuclear Information System (INIS)

Baars, R.E.

1976-01-01

The Damage Parameter (DP) empirical correlation of fuel pin cladding failure thresholds for TOP events has been revised and recorrelated to the results of twelve TREAT tests. The revised correlation, called the Failure Potential (FP) correlation, predicts failure times for the tests in the data base with an average error of 35 ms for $3/s tests and of 150 ms for 50 cents/s tests
Incidence and predictors of 6 months mortality after an acute heart failure event in rural Uganda: The Mbarara Heart Failure Registry (MAHFER).

Science.gov (United States)

Abeya, Fardous Charles; Lumori, Boniface Amanee Elias; Akello, Suzan Joan; Annex, Brian H; Buda, Andrew J; Okello, Samson

2018-03-29

We sought to estimate the incidence and predictors of all-cause mortality 6 months after heart failure hospitalization in Uganda. Mbarara Heart Failure Registry is a cohort of patients hospitalized with a clinical diagnosis of heart failure at Mbarara Regional Referral Hospital, Uganda. We measured serum electrolytes, cardiac markers, and echocardiograms. All participants were followed until death or end of 6 months. We used Fine and Gray models to estimate the incidence and predictors all-cause mortality. A total of 215 participants were enrolled, 141 (66%) were women, and mean age 53 (standard deviation 22) years. Nineteen (9%) had diabetes, 40 (19%) had HIV, and 119 (55%) had hypertension. The overall incidence of all-cause mortality was 3.58 (95% CI 2.92, 4.38) per 1000 person-days. Men had higher incidence of death compared to women (4.02 vs 3.37 per 1000 person-days). The incidence of all-cause mortality during hospitalization was almost twice that of in the community (27.5 vs 14.77 per 1000 person-days). In adjusted analysis, increasing age, NYHA class IV, decreasing renal function, smoking, each unit increase in serum levels of Potassium, BNP, and Creatine kinase-MB predicted increased incidence of 6 months all-cause death whereas taking beta-blockers and having an index admission on a weekend compared to a week day predicted survival. There is a high incidence of all-cause mortality occurring in-hospital among patients hospitalized with heart failure in rural Uganda. Heart failure directed therapies should be instituted to curb heart failure-related mortality. Copyright © 2017 Elsevier B.V. All rights reserved.
Unusual Etiology and Diagnosis of Oroantral Communication due to Late Implant Failure

Directory of Open Access Journals (Sweden)

Rabah Nedir

2017-01-01

Full Text Available Oroantral communication (OAC rarely occurs long after implant placement. The present report describes the rare etiology and the difficulty of the diagnosis of an uncommon OAC occurring 10 years after the implant placement in the posterior maxilla. The difficulty of the diagnosis lies in the absence of clinical symptoms of sinusitis and presence of multiunit prosthesis hiding implant failure. This case report supports the need for sinus check-up during a routine implant examination.
Analysis of unprotected overcooling events in the Integral Fast Reactor

International Nuclear Information System (INIS)

Vilim, R.B.

1989-01-01

Simple analytic models are developed for predicting the response of a metal fueled, liquid-metal cooled reactor to unprotected overcooling events in the balance of plant. All overcooling initiators are shown to fall into two categories. The first category contains these events for which there is no final equilibrium state of constant overcooling, as in the case for a large steam leak. These events are analyzed using a non-flow control mass approach. The second category contains those events which will eventually equilibrate, such as a loss of feedwater heaters. A steady flow control volume analysis shows that these latter events ultimately affect the plant through the feedwater inlet to the steam generator. The models developed for analyzing these two categories provide upper bounds for the reactor's passive response to overcooling accident initiators. Calculation of these bounds for a prototypic plant indicate that failure limits -- eutectic melting, sodium boiling, fuel pin failure -- are not exceeded in any overcooling event. 2 refs
Assessment of the impact of fueling machine failure on the safety of the CANDU-PHWR

International Nuclear Information System (INIS)

Al-Kusayer, T.A.

1982-01-01

A survey of possible LOCA (Loss-of-Coolant Accident) initiating events that might take place for CANDU-PHWRs (Canadian Deuterium Uranium-Pressurized Heavy Water Reactors) has been conducted covering both direct and indirect initiators. Among the 22 initiating events that were surveyed in this study, four direct initiators have been selected and analyzed briefly. Those selected were a pump suction piping break, an isolation valve piping break, a bleed valve failure, and a fueling machine interface failure. These were selected as examples of failures that could take place in the inlet side, outlet side, or PHTS (Primary Heat Transport System) interfaces. The Pickering NGS (Unit-A) was used for this case study. Double failure (failure of the protective devices to operate when the process equipment fault occurs) and a triple failure (failure of the protective devices and the ECCS as well as the process equipment) were found to be highly improbable
Common cause failure data collection and analysis for safety-related components of TRIGA SSR-14MW Pitesti, Romania

International Nuclear Information System (INIS)

Radu, G.; Mladin, D.

2003-01-01

This paper presents a study performed on the set of common cause failures (CCF) of safety-related components of the research reactor TRIGA SSR-14 MW Pitesti. The data collected cover a period of 20 years, from 1979 to 2000. The sources of data are Shift Supervisor Reports, Work Authorizations, and Reactor Log Books. Events collected are analyzed by failure mode and degrees of failure. Qualitative analysis of root causes, coupling factors and corrective actions and quantitative analysis of CCF events are studied. The objective of this work is to develop qualitative insights in the nature of the reported events and to build a site-specific common cause events database. (author)
Prognostic factors for perioperative pulmonary events among patients undergoing upper abdominal surgery

Directory of Open Access Journals (Sweden)

Rafael Luis Sakai

Full Text Available CONTEXT AND OBJECTIVE: The significant relationship between upper abdominal surgery and early (perioperative pulmonary events was investigated among patients with preoperative pulmonary conditions undergoing general anesthesia. DESIGN AND SETTING: Retrospective study for which data were obtained prospectively from 1999 to 2004, at a tertiary university hospital. METHODS: We retrospectively studied 3107 patients over 11 years old presenting American Society of Anesthesiologists (ASA status I, II or III who underwent upper abdominal surgery under general anesthesia and were discharged to the recovery room. The preoperative conditions analyzed using logistic regression were: age, sex, ASA physical status, congestive heart failure, asthma, chronic obstructive pulmonary disease (COPD, respiratory failure and smoking. The outcomes or dependent variables included intraoperative and postoperative events: bronchospasm, hypoxemia, hypercapnia, prolonged intubation and airway secretion. RESULTS: Among these patients (1500 males, 1607 females, mean age 48 years, 1088 ASA I, 1402 ASA II and 617 ASA III, there were 80 congestive heart failures, 82 asthmatics, 122 with COPD, 21 respiratory failures and 428 smokers. Logistic regression analysis showed that female sex (p < 0.001, age over 70 years (p < 0.01, smoking (p < 0.001 and COPD (p < 0.02 significantly influenced pulmonary event development, particularly hypoxemia and bronchospasm, at both times but not in the same patients. Asthma and congestive heart failure cases did not present pulmonary events in the recovery room. CONCLUSION: In upper abdominal surgery under general anesthesia, female sex, age over 70, smoking and COPD were independent risk factors for intra and postoperative pulmonary events.
Trend analysis of breaker events at United States nuclear power plants

International Nuclear Information System (INIS)

Shimada, Hiroki

2006-01-01

From events in overseas nuclear power plants recorded in the nuclear information detabase of Institute of Nuclear Safety System, Inc. (INSS), the number of events of electrical systems during the four years from 2002 to 2005 was extracted and the trend was analyzed. The results showed that breaker events were the largest in number in all years, and almost all them occurred in the US. The breaker events that occurred in US nuclear power plants in 2005 were analyzed by classifying them by cause of failure and effect on the plant, and by comparing the number of occurrences with that in Japan. As a result, the main cause of many of the breaker events was improper maintenance due to poor arrangement of maintenance manuals and human error, as well as aging degradation, they can be estimated to have been caused by insufficient maintenance control and inspection. The number of breaker failures per plant per year in our country was lower than that in the US by an order of magnitude, and there were no failures that led to a plant trip or power reduction. These facts suggest that our country's maintenance contents of breaker are advantage. (author)
Predictive Sampling of Rare Conformational Events in Aqueous Solution: Designing a Generalized Orthogonal Space Tempering Method.

Science.gov (United States)

Lu, Chao; Li, Xubin; Wu, Dongsheng; Zheng, Lianqing; Yang, Wei

2016-01-12

In aqueous solution, solute conformational transitions are governed by intimate interplays of the fluctuations of solute-solute, solute-water, and water-water interactions. To promote molecular fluctuations to enhance sampling of essential conformational changes, a common strategy is to construct an expanded Hamiltonian through a series of Hamiltonian perturbations and thereby broaden the distribution of certain interactions of focus. Due to a lack of active sampling of configuration response to Hamiltonian transitions, it is challenging for common expanded Hamiltonian methods to robustly explore solvent mediated rare conformational events. The orthogonal space sampling (OSS) scheme, as exemplified by the orthogonal space random walk and orthogonal space tempering methods, provides a general framework for synchronous acceleration of slow configuration responses. To more effectively sample conformational transitions in aqueous solution, in this work, we devised a generalized orthogonal space tempering (gOST) algorithm. Specifically, in the Hamiltonian perturbation part, a solvent-accessible-surface-area-dependent term is introduced to implicitly perturb near-solute water-water fluctuations; more importantly in the orthogonal space response part, the generalized force order parameter is generalized as a two-dimension order parameter set, in which essential solute-solvent and solute-solute components are separately treated. The gOST algorithm is evaluated through a molecular dynamics simulation study on the explicitly solvated deca-alanine (Ala10) peptide. On the basis of a fully automated sampling protocol, the gOST simulation enabled repetitive folding and unfolding of the solvated peptide within a single continuous trajectory and allowed for detailed constructions of Ala10 folding/unfolding free energy surfaces. The gOST result reveals that solvent cooperative fluctuations play a pivotal role in Ala10 folding/unfolding transitions. In addition, our assessment
Failure probability under parameter uncertainty.

Science.gov (United States)

Gerrard, R; Tsanakas, A

2011-05-01

In many problems of risk analysis, failure is equivalent to the event of a random risk factor exceeding a given threshold. Failure probabilities can be controlled if a decisionmaker is able to set the threshold at an appropriate level. This abstract situation applies, for example, to environmental risks with infrastructure controls; to supply chain risks with inventory controls; and to insurance solvency risks with capital controls. However, uncertainty around the distribution of the risk factor implies that parameter error will be present and the measures taken to control failure probabilities may not be effective. We show that parameter uncertainty increases the probability (understood as expected frequency) of failures. For a large class of loss distributions, arising from increasing transformations of location-scale families (including the log-normal, Weibull, and Pareto distributions), the article shows that failure probabilities can be exactly calculated, as they are independent of the true (but unknown) parameters. Hence it is possible to obtain an explicit measure of the effect of parameter uncertainty on failure probability. Failure probability can be controlled in two different ways: (1) by reducing the nominal required failure probability, depending on the size of the available data set, and (2) by modifying of the distribution itself that is used to calculate the risk control. Approach (1) corresponds to a frequentist/regulatory view of probability, while approach (2) is consistent with a Bayesian/personalistic view. We furthermore show that the two approaches are consistent in achieving the required failure probability. Finally, we briefly discuss the effects of data pooling and its systemic risk implications. © 2010 Society for Risk Analysis.
An observational study of the frequency, severity, and etiology of failures in postoperative care after major elective general surgery.

Science.gov (United States)

Symons, Nicholas R A; Almoudaris, Alex M; Nagpal, Kamal; Vincent, Charles A; Moorthy, Krishna

2013-01-01

To investigate the nature of process failures in postoperative care, to assess their frequency and preventability, and to explore their relationship to adverse events. Adverse events are common and are frequently caused by failures in the process of care. These processes are often evaluated independently using clinical audit. There is little understanding of process failures in terms of their overall frequency, relative risk, and cumulative effect on the surgical patient. Patients were observed daily from the first postoperative day until discharge by an independent surgeon. Field notes on the circumstances surrounding any nonroutine or atypical event were recorded. Field notes were assessed by 2 surgeons to identify failures in the process of care. Preventability, the degree of harm caused to the patient, and the underlying etiology of process failures were evaluated by 2 independent surgeons. Fifty patients undergoing major elective general surgery were observed for a total of 659 days of postoperative care. A total of 256 process failures were identified, of which 85% were preventable and 51% directly led to patient harm. Process failures occurred in all aspects of care, the most frequent being medication prescribing and administration, management of lines, tubes, and drains, and pain control interventions. Process failures accounted for 57% of all preventable adverse events. Communication failures and delays were the main etiologies, leading to 54% of process failures. Process failures are common in postoperative care, are highly preventable, and frequently cause harm to patients. Interventions to prevent process failures will improve the reliability of surgical postoperative care and have the potential to reduce hospital stay.

Adult primary hypoparathyroidism: A rare presentation

Directory of Open Access Journals (Sweden)

Ashima Datey Chakrabarty

2013-01-01

Full Text Available The common causes of stridor in adults are abscesses or swelling of upper airway, tumors, paralysis or malfunction of vocal cords. Laryngospasm due to hypocalcemia is a rare cause of stridor in adults, although occasionally reported in the neonates. We report an elderly lady having stridor and laryngospasm, secondary to acquired hypoparathyroidism and secondary hypocalcemia, without risk factors for hypoparathyroidism such as recent neck surgery or irradiation. We did an extensive review of literature to find only a few cases of acquired primary hypoparathyroidism in adults with the only complaint being stridor. This case underlines the fact that a common symptom like stridor rarely occurs due to uncommon causes. This case is being reported for its rarity and amenability to complete cure in event of correct diagnosis.
A patient with a rare leukodystrophy related to lamin B1 duplication.

LENUS (Irish Health Repository)

Molloy, A

2012-06-01

The hereditary leukodystrophies are rare disorders caused by molecular abnormalities leading to destruction of or failure of development of central white matter. For almost 30 years there has been increasing recognition of later onset Autosomal Dominant Leukodystrophy (ADLD). We report the first genetically confirmed case of lamin B1 duplication causing ADLD from Ireland.
A study on the regulatory approach of KNGR multiple failure events

Energy Technology Data Exchange (ETDEWEB)

Chang, Keun Sun; Kweon, Y. C.; Kang, H. J.; Lee, S. J.; Lee, Y. S.; Moon, J. J.; Lee, M. K. [Sumoon Univ., Asan (Korea, Republic of); Jeong, Ji Hwan [Baekseok College, Cheonan (Korea, Republic of); Yang, S. H. [Korea Association for Nuclear Technology, Taejon (Korea, Republic of)

2000-02-15

This project is to provide the regulatory direction of 3 major technical issues for the Korean Next Generation Reactors, which are parts of major technical issues resulted from the safety regulation R and D on the KNGR. The outstanding results are as follows : through comparison and analysis of domestic/international requirements related to SBO, additional items, which are considered in SSRs, are identified. According to investigation, procedure and training should be included in SSRs, and plant-specific capability analysis requirement contains initial condition, acceptance and addition analysis on the leak rake through RCP seal, etc. In addition, state of the art on the major items related to SBO requirement are described. Several safety analysis requirements are suggested that are needed to be used in the analyses which are aiming to show the ability of the SDVS to cope with TLOFW event. The suggested requirements include suggestions in BE method, reactor thermal power and decay heat, time to reactor trip, time to RCP trip, operator response time, pressurizer and steam generator, and thermal-hydraulic models related to TLOFW event. It is recommended that Moody model mentioned in 10CFR50 appendix K should be excluded in calculation of discharge flow through bleed valves in case of a TLOFW event. Some requirements on initial and boundary conditions are suggested to be used in the analyses of NPPs during MSGTR events. The suggestion includes requirements on analysis method, number of reptured tubes, repture location, operator response time, primary coolant leak flow, and acceptance criteria. As there has been no occurrence of MSGTR event and little literatures reporting analysis results of the event, some items need more study. In addition, some analyses are needed in order to fine the rupture location which gives the most conservative consequence.
A study on the regulatory approach of KNGR multiple failure events

International Nuclear Information System (INIS)

Chang, Keun Sun; Kweon, Y. C.; Kang, H. J.; Lee, S. J.; Lee, Y. S.; Moon, J. J.; Lee, M. K.; Jeong, Ji Hwan; Yang, S. H.

2000-02-01

This project is to provide the regulatory direction of 3 major technical issues for the Korean Next Generation Reactors, which are parts of major technical issues resulted from the safety regulation R and D on the KNGR. The outstanding results are as follows : through comparison and analysis of domestic/international requirements related to SBO, additional items, which are considered in SSRs, are identified. According to investigation, procedure and training should be included in SSRs, and plant-specific capability analysis requirement contains initial condition, acceptance and addition analysis on the leak rake through RCP seal, etc. In addition, state of the art on the major items related to SBO requirement are described. Several safety analysis requirements are suggested that are needed to be used in the analyses which are aiming to show the ability of the SDVS to cope with TLOFW event. The suggested requirements include suggestions in BE method, reactor thermal power and decay heat, time to reactor trip, time to RCP trip, operator response time, pressurizer and steam generator, and thermal-hydraulic models related to TLOFW event. It is recommended that Moody model mentioned in 10CFR50 appendix K should be excluded in calculation of discharge flow through bleed valves in case of a TLOFW event. Some requirements on initial and boundary conditions are suggested to be used in the analyses of NPPs during MSGTR events. The suggestion includes requirements on analysis method, number of reptured tubes, repture location, operator response time, primary coolant leak flow, and acceptance criteria. As there has been no occurrence of MSGTR event and little literatures reporting analysis results of the event, some items need more study. In addition, some analyses are needed in order to fine the rupture location which gives the most conservative consequence
Fulminant hepatic failure in an infant with severe dengue infection.

Science.gov (United States)

Soundravally, R; Narayanan, P; Bhat, B Vishnu; Soundraragavan, Jayanthi; Setia, Sajita

2010-04-01

Fulminant hepatic failure due to dengue infection is rare, although mild liver dysfunction is common. Here we report a fatal case of fulminant hepatitis in an infant infected with dengue 3 serotype. Attention must be given to the use of hepatotoxic drugs in some cases of dengue especially in infants.
Dependencies in event trees analyzed by Petri nets

International Nuclear Information System (INIS)

Nývlt, Ondřej; Rausand, Marvin

2012-01-01

This paper discusses how non-marked Petri nets can be used to model and analyze event trees where the pivotal (branching) events are dependent and modeled by fault trees. The dependencies may, for example, be caused by shared utilities, shared components, or general common cause failures that are modeled by beta-factor models. These dependencies are cumbersome to take into account when using standard event-/fault tree modeling techniques, and may lead to significant errors in the calculated end-state probabilities of the event tree if they are not properly analyzed. A new approach is proposed in this paper, where the whole event tree is modeled by a non-marked Petri net and where P-invariants, representing the structural properties of the Petri net, are used to obtain the frequency of each end-state of the event tree with dependencies. The new approach is applied to a real example of an event tree analysis of the Strahov highway tunnel in Prague, Czech Republic, including two types of dependencies (shared Programmable Logic Controllers and Common Cause Failures). - Highlights: ► In this paper, we model and analyze event trees (ET) using Petri nets. ► The pivotal events of the modeled event trees are dependent (e.g., shared PLCs, CCF). ► A new method based on P-invariants to obtain probabilities of end states is proposed. ► Method is shown in the case study of the Stahov tunnel in the Czech Republic.
Risk factors for venous thromboembolic events in pediatric surgical patients: Defining indications for prophylaxis.

Science.gov (United States)

Cairo, Sarah B; Lautz, Timothy B; Schaefer, Beverly A; Yu, Guan; Naseem, Hibbut-Ur-Rauf; Rothstein, David H

2017-12-27

Venous thromboembolism (VTE) in pediatric surgical patients is a rare event. The risk factors for VTE in pediatric general surgery patients undergoing abdominopelvic procedures are unknown. The American College of Surgeon's National Surgical Quality Improvement Program-Pediatric (NSQIP-P) database (2012-2015) was queried for patients with VTE after abdominopelvic general surgery procedures. Patient and operative variables were assessed to identify risk factors associated with VTE and develop a pediatric risk score. From 2012-2015, 68 of 34,813 (0.20%) patients who underwent abdominopelvic general surgery procedures were diagnosed with VTE. On multivariate analysis, there was no increased risk of VTE based on concomitant malignancy, chemotherapy, inflammatory bowel disease, or laparoscopic surgical approach, while a higher rate of VTE was identified among female patients. The odds of experiencing VTE were increased on stepwise regression for patients older than 15 years and those with preexisting renal failure or a diagnosis of septic shock, patients with American Society of Anesthesia (ASA) classification ≥ 2, and for anesthesia time longer than 2 h. The combination of age > 15 years, ASA classification ≥ 2, anesthesia time > 2 h, renal failure, and septic shock was included in a model for predicting risk of VTE (AUC = 0.907, sensitivity 84.4%, specificity 88.2%). VTE is rare in pediatric patients, but prediction modeling may help identify those patients at heightened risk. Additional studies are needed to validate the factors identified in this study in a risk assessment model as well as to assess the efficacy and cost-effectiveness of prophylaxis methods. Level III, retrospective comparative study. Copyright © 2018. Published by Elsevier Inc.
Recurring events - Volume 2

International Nuclear Information System (INIS)

2003-04-01

known, thus the actions taken were not effective in preventing recurrence of an event, - The contributing factors or causes of the event were not taken into account in defining the actions to be taken. Several good practices were identified to prevent recurring events. These practices are part of related guides provided by national and international bodies. Some of these are: - NPPs should analyse recurring events in-depth, in order to identify root causes and contributing factors to prevent further recurrence. The specific factors that failed to prevent recurrence should be investigated and identified (that is, why prior operating experience was not effectively applied). - For minor events, trend analyses should be performed to monitor the frequency of component failures (which may be unavoidable) or the frequency of minor human performance problems (which may indicate weaknesses in error prevention processes and programs). - Analysis of external operating experiences from other NPPs should be strengthened to broaden the basis for preventive measures; - Actions taken after events should be assessed regarding their effectiveness in preventing recurrence of similar events. Subsequent to the workshop, a more detailed search of reports of operating experience, including IRS and other reports from national sources, resulted in the determination of a number of recurring categories: - Loss of RHR at mid-loop (in the 1999 report also); - BWR instability (in the 1999 report also); - PWR vessel corrosion due to boric acid effects; - Hydrogen detonation in BWR piping; - Steam Generator Tube Rupture; - Multiple valve failures in ECCS; - Service Water Failure due to Marine Biofouling (in the 1999 report also); - System Level Failures with Human Factors Considerations; - Strainer Clogging (sources of emergency injection or recirculation). Five conclusions were established on the basis of the workshop and the recurring event analysis: Conclusion 1: Recurring events continue to be
Insights About Emergency Diesel Generator Failures from the USNRC's Common Cause Failure Database

International Nuclear Information System (INIS)

Mosleh, A.; Rasmuson, D.; Marshall, F.; Wierman, T.

1999-01-01

The US Nuclear Regulatory Commission has sponsored development of a database of common cause failure events for use in commercial nuclear power plant risk and reliability analyses. This paper presents a summary of the results from analysis of the emergency diesel generator data from the database. The presentation is limited to the overall insights, the design and manufacturing cause and the instrumentation and control sub-system
Acromegaly with Normal Insulin-Like Growth Factor-1 Levels and Congestive Heart Failure as the First Clinical Manifestation

Directory of Open Access Journals (Sweden)

Hyae Min Lee

2015-09-01

Full Text Available The leading cause of morbidity and mortality in patients with acromegaly is cardiovascular complications. Myocardial exposure to excessive growth hormone can cause ventricular hypertrophy, hypertension, arrhythmia, and diastolic dysfunction. However, congestive heart failure as a result of systolic dysfunction is observed only rarely in patients with acromegaly. Most cases of acromegaly exhibit high levels of serum insulin-like growth factor-1 (IGF-1. Acromegaly with normal IGF-1 levels is rare and difficult to diagnose. Here, we report a rare case of an acromegalic patient whose first clinical manifestation was severe congestive heart failure, despite normal IGF-1 levels. We diagnosed acromegaly using a glucose-loading growth hormone suppression test. Cardiac function and myocardial hypertrophy improved 6 months after transsphenoidal resection of a pituitary adenoma.
Estimation of initiating event distribution at nuclear power plants by Bayesian procedure

International Nuclear Information System (INIS)

Chen Guangming

1995-01-01

Initiating events at nuclear power plants such as human errors or components failures may lead to a nuclear accident. The study of the frequency of these events or the distribution of the failure rate is necessary in probabilistic risk assessment for nuclear power plants. This paper presents Bayesian modelling methods for the analysis of the distribution of the failure rate. The method can also be utilized in other related fields especially where the data is sparse. An application of the Bayesian modelling in the analysis of distribution of the time to recover Loss of Off-Site Power ( LOSP) is discussed in the paper
Development of a GIS-based failure investigation system for highway soil slopes

Science.gov (United States)

Ramanathan, Raghav; Aydilek, Ahmet H.; Tanyu, Burak F.

2015-06-01

A framework for preparation of an early warning system was developed for Maryland, using a GIS database and a collective overlay of maps that highlight highway slopes susceptible to soil slides or slope failures in advance through spatial and statistical analysis. Data for existing soil slope failures was collected from geotechnical reports and field visits. A total of 48 slope failures were recorded and analyzed. Six factors, including event precipitation, geological formation, land cover, slope history, slope angle, and elevation were considered to affect highway soil slope stability. The observed trends indicate that precipitation and poor surface or subsurface drainage conditions are principal factors causing slope failures. 96% of the failed slopes have an open drainage section. A majority of the failed slopes lie in regions with relatively high event precipitation ( P>200 mm). 90% of the existing failures are surficial erosion type failures, and only 1 out of the 42 slope failures is deep rotational type failure. More than half of the analyzed slope failures have occurred in regions having low density land cover. 46% of failures are on slopes with slope angles between 20° and 30°. Influx of more data relating to failed slopes should give rise to more trends, and thus the developed slope management system will aid the state highway engineers in prudential budget allocation and prioritizing different remediation projects based on the literature reviewed on the principles, concepts, techniques, and methodology for slope instability evaluation (Leshchinsky et al., 2015).
Newly diagnosed primary hypothyroidism applicant with massive pericardial effusion and acute renal failure

Directory of Open Access Journals (Sweden)

Ates I

2016-01-01

Full Text Available Objective. While non-symptomatic pericardial effusion is seen in primary hypothyroidism, massive pericardial effusion is a very rare finding. In the literature, newly diagnosed primary hypothyroidism cases presenting with massive pericardial effusion or acute renal failure are present, but we did not encounter any case first presenting with combination of two signs. In this case report, primary hypothyroidism case that presenting with massive pericardial effusion and acute renal failure will be discussed.
42 CFR 23.28 - What events constitute default?

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false What events constitute default? 23.28 Section 23.28 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES PERSONNEL NATIONAL HEALTH... default? The following events will constitute defaults of the loan agreement: (a) Failure to make full...
A case of peripartum heart failure

Directory of Open Access Journals (Sweden)

Annalisa Vinci

2008-03-01

Full Text Available A 32-year-old woman was admitted in congestive heart failure (CHF 3 days after delivery. She had no history of cardiovascular disease and impaired left ventricular Ejection Fraction (EF 35%. She underwent complete heart catheterisation, selective coronary angiography and right ventricular endomyocardial biopsy (EMB.Coronary arteries were normal and EMB revealed active virus negative myocarditis. Serum was positive for anti-heart autoantibodies (AHA. Thus myocarditis was classified as autoimmune and the patient was treated with immunosuppressive therapy, with clinical and hemodynamic improvement. At 27 months follow-up EMB showed healed myocarditis. Peripartum cardiomyopathy (PPCM is a rare disorder in which left ventricular dysfunction and heart failure occur in the peripartum period in previously healthy women. The etiology is still unknown but a sizable proportion of patients may have an underlying organ-specific autoimmune myocarditis.
Star fruit (Averrhoa carambola) intoxication: an important cause of consciousness disturbance in patients with renal failure.

Science.gov (United States)

Chang, Chin-Tung; Chen, Yung-Chang; Fang, Ji-Tseng; Huang, Chiu-Ching

2002-05-01

Star fruit intoxication is a rare cause of consciousness disturbance in patients with renal failure. Most cases in the literature are uremic patients on maintenance dialysis. We present a patient with chronic renal failure, who was not on dialysis program yet, suffered from star fruit intoxication with presentation of consciousness disturbance and successfully managed by a session of hemodialysis.
Preliminary failure modes and effects analysis on Korean HCCR TBS to be tested in ITER

International Nuclear Information System (INIS)

Ahn, Mu-Young; Cho, Seungyon; Jin, Hyung Gon; Lee, Dong Won; Park, Yi-Hyun; Lee, Youngmin

2015-01-01

Highlights: • Postulated initiating events are identified through failure modes and effects analysis on the current HCCR TBS design. • A set of postulated initiating events are selected for consideration of deterministic analysis. • Accident evolutions on the selected postualted initiating events are qualitatively described for deterministic analysis. - Abstract: Korean Helium cooled ceramic reflector (HCCR) Test blanket system (TBS), which comprises Test blanket module (TBM) and ancillary systems in various locations of ITER building, is operated at high temperature and pressure with decay heat. Therefore, safety is utmost concern in design process and it is required to demonstrate that the HCCR TBS is designed to comply with the safety requirements and guidelines of ITER. Due to complexity of the system with many interfaces with ITER, a systematic approach is necessary for safety analysis. This paper presents preliminary failure modes and effects analysis (FMEA) study performed for the HCCR TBS. FMEA is a systematic methodology in which failure modes for components in the system and their consequences are studied from the bottom-up. Over eighty failure modes have been investigated on the HCCR TBS. The failure modes that have similar consequences are grouped as postulated initiating events (PIEs) and total seven reference accident scenarios are derived from FMEA study for deterministic accident analysis. Failure modes not covered here due to evolving design of the HCCR TBS and uncertainty in maintenance procedures will be studied further in near future.
Preliminary failure modes and effects analysis on Korean HCCR TBS to be tested in ITER

Energy Technology Data Exchange (ETDEWEB)

Ahn, Mu-Young, E-mail: myahn74@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of); Jin, Hyung Gon; Lee, Dong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi-Hyun; Lee, Youngmin [National Fusion Research Institute, Daejeon (Korea, Republic of)

2015-10-15

Highlights: • Postulated initiating events are identified through failure modes and effects analysis on the current HCCR TBS design. • A set of postulated initiating events are selected for consideration of deterministic analysis. • Accident evolutions on the selected postualted initiating events are qualitatively described for deterministic analysis. - Abstract: Korean Helium cooled ceramic reflector (HCCR) Test blanket system (TBS), which comprises Test blanket module (TBM) and ancillary systems in various locations of ITER building, is operated at high temperature and pressure with decay heat. Therefore, safety is utmost concern in design process and it is required to demonstrate that the HCCR TBS is designed to comply with the safety requirements and guidelines of ITER. Due to complexity of the system with many interfaces with ITER, a systematic approach is necessary for safety analysis. This paper presents preliminary failure modes and effects analysis (FMEA) study performed for the HCCR TBS. FMEA is a systematic methodology in which failure modes for components in the system and their consequences are studied from the bottom-up. Over eighty failure modes have been investigated on the HCCR TBS. The failure modes that have similar consequences are grouped as postulated initiating events (PIEs) and total seven reference accident scenarios are derived from FMEA study for deterministic accident analysis. Failure modes not covered here due to evolving design of the HCCR TBS and uncertainty in maintenance procedures will be studied further in near future.
What, if anything, is specific about having a rare disorder? Patients’ judgements on being ill and being rare

Science.gov (United States)

Huyard, Caroline

2009-01-01

Abstract Background Growing efforts are made to improve the situation of persons with rare diseases, but the specific nature of these disorders remains unclear. Objectives To establish (1) to what extent people with rare disorders think that their disease’s rarity causes particular difficulties, (2) to what extent these difficulties relate to other causes than rarity (i.e. other characteristics of the disease or other components of the illness experience), (3) to what extent the rarity of the disease may relate to components of patients’ experience other than those that are traditionally addressed (i.e. personal or daily life aspects). Methods Semi‐structured interviews with 29 patients and 15 parents of children with one of six rare diseases (cystic fibrosis, fragile X syndrome, Wilson’s disease, mastocytosis, locked‐in syndrome and a sixth syndrome). The interviews were conducted in France. The analysis draws on French pragmatic sociology and focuses on the participants’ judgements of their experience. Findings The participants considered as normal and acceptable a range of situations that are often viewed as specific to rare disorders and unfair. This rather positive evaluation was conditional on some specific moral criteria being met. The participants attributed the cause of their difficulties to the failure of health professionals to meet these criteria. In the participants’ experience, disease‐related associations play a key role and rarity seems to contribute to making them especially important. Conclusions Patients’ experience would be considerably improved if health professionals more often fulfilled their moral expectations, especially regarding diagnosis disclosure and information. (250 words) PMID:19840131
Corrosion induced failure analysis of subsea pipelines

International Nuclear Information System (INIS)

Yang, Yongsheng; Khan, Faisal; Thodi, Premkumar; Abbassi, Rouzbeh

2017-01-01

Pipeline corrosion is one of the main causes of subsea pipeline failure. It is necessary to monitor and analyze pipeline condition to effectively predict likely failure. This paper presents an approach to analyze the observed abnormal events to assess the condition of subsea pipelines. First, it focuses on establishing a systematic corrosion failure model by Bow-Tie (BT) analysis, and subsequently the BT model is mapped into a Bayesian Network (BN) model. The BN model facilitates the modelling of interdependency of identified corrosion causes, as well as the updating of failure probabilities depending on the arrival of new information. Furthermore, an Object-Oriented Bayesian Network (OOBN) has been developed to better structure the network and to provide an efficient updating algorithm. Based on this OOBN model, probability updating and probability adaptation are performed at regular intervals to estimate the failure probabilities due to corrosion and potential consequences. This results in an interval-based condition assessment of subsea pipeline subjected to corrosion. The estimated failure probabilities would help prioritize action to prevent and control failures. Practical application of the developed model is demonstrated using a case study. - Highlights: • A Bow-Tie (BT) based corrosion failure model linking causation with the potential losses. • A novel Object-Oriented Bayesian Network (OOBN) based corrosion failure risk model. • Probability of failure updating and adaptation with respect to time using OOBN model. • Application of the proposed model to develop and test strategies to minimize failure risk.

Imaging of Kaposi sarcoma in a transplanted liver: A rare case report

Directory of Open Access Journals (Sweden)

Saumya Gupta

2015-06-01

Full Text Available In post-transplant patients, de novo malignancies such as post-transplant lymphoproliferative disease (PTLD, lung carcinoma, renal cell carcinoma, cutaneous malignancies, and Kaposi sarcoma are now seen. The immunotherapy used to prevent graft failure indirectly increases their risk. We present a rare case of visceral Kaposi sarcoma in a patient with orthotopic liver transplant.
Development and validation of a taxonomy of adverse handover events in hospital settings

DEFF Research Database (Denmark)

Andersen, Henning Boje; Siemsen, Inger Margrete D.; Petersen, Lene Funck

2015-01-01

Patient Safety Database, 200 events) and 47 interviews with staff conducted at a large hospital in the Capital Region (232 events). The most prevalent causes of adverse events are inadequate competence (30 %), inadequate infrastructure (22 %) and busy ward (18 %). Inter-rater reliability (kappa) was 0.......76 and 0.87 for reports and interviews, respectively. Communication in clinical contexts has been widely recognized as giving rise to potentially hazardous events, and handover situations are particularly prone to failures of communication or unclear allocation of responsibility. The taxonomy provides...... a tool for analyzing adverse handover events to identify frequent causes among reported handover failures. In turn, this provides a basis for selecting safety measures including handover protocols and training programmes....
A case of congestive heart failure induced by therapeutic irradiation

International Nuclear Information System (INIS)

Kushigami, Motohiko; Suruda, Hidetoshi; Mizukoshi, Masato; Umemoto, Masaaki; Fujiwara, Setsuko; Yamamoto, Katsuhiro; Ueno, Yuji; Nishio, Ichiro; Masuyama, Yoshiaki

1985-01-01

Valvular insufficiency in radiation-induced heart disease is very rare. We described a patient, 53 years old woman, who developed congestive heart failure 2.5 years later following radiotherapy for esophageal carcinoma. The findings on examinations including cardiac catheterization revealed pericarditis with effusion, mitral and tricuspid valve insufficiency and pulmonary infarction. (author)
Prognostic value of myocardial perfusion and ventricular function in a Japanese multicenter cohort study (J-ACCESS). The first-year total events and hard events

International Nuclear Information System (INIS)

Nakajima, Kenichi; Kusuoka, Hideo; Nishimura, Shigeyuki; Yamashina, Akira; Nishimura, Tsunehiko

2009-01-01

The objective of this study was to determine the prognostic value of myocardial ischemia, function and coronary risk factors on total and hard cardiac events using myocardial perfusion imaging in a Japanese population. A prospective cohort study was performed in 117 Japanese hospitals, each with a nuclear cardiology facility. A total of 4,031 patients with suspected or confirmed ischemic heart disease were registered. The patients were followed up for a year to investigate total and hard events, and those who had any events were followed up for 3 years to evaluate subsequent hard events. A stress-rest gated myocardial perfusion study was performed with 99m Tc-tetrofosmin using gated single-photon emission computed tomography (SPECT) and analyzed by semi-quantitative scores. During the 1-year follow-up period, 263 (6.5%) patients had total events comprising all-cause death, non-fatal myocardial infarction (MI), heart failure, unstable angina, angina pectoris and coronary revascularization. Cardiac death occurred in 23 patients (0.6%) and non-fatal MI in 11 (0.3%). Among patients with ejection fraction (EF) of <45% and a summed difference score (SDS) of ≥2, 18.7% (2.4% for cardiac death and 0.6% for non-fatal MI) experienced total events compared with 3.9% (0.3% for cardiac death and 0.2% for non-fatal MI; P<0.0001) of those with EF≥45% and SDS<2. Multivariate analysis identified EF, SDS, age, history of revascularization and diabetes as significant predictors of all events, while the significant predictors were age and EF for hard events. When the patients who had heart failure in the first year were followed up, 9 of 41 (22.0%) experienced cardiac death in the subsequent 3-year follow-up period. Myocardial ischemia defined by SDS and ventricular function were the main predictors of total events despite the relatively low incidence of hard events in this Japanese population. In patients with cardiac events in a year, closer attention should be paid to subsequent
Safety relevant failure mechanisms in the post-operational phase; Sicherheitstechnisch relevante Fehlermechanismen in der Nachbetriebsphase

Energy Technology Data Exchange (ETDEWEB)

Mayer, Gerhard; Stiller, Jan Christopher; Roemer, Sarah

2017-03-15

. Finally, national and international operating experience was evaluated with the aim to derive general failure mechanisms from events that have occurred. For this purpose, the database of German reportable events (VERA), the database of the OECD/NEA ''International Common-cause Data Exchange (ICDE)'' project as well as the database of the ''International Reporting Systems for Operating Experience (IRS)'' of the IAEA was searched. As these data sources comprise a total number of about 12,000 events, initially the evaluation focused on the 309 events that occurred in plants that are in the post operation or decommissioning phase. In order to capture events from power operation whose damage phenomena have special relevance for post operation, too, attempts were made to develop automatic searches that would deliver a pre-selection of relevant results. To evaluate this method, 900 events from a German twin unit plant over a period from their construction until the present were analysed manually. It turned out that an automated search did not deliver enveloping results. All in all, 12 events from German plants in post operation or decommissioning and 36 events from plants with power operation licences as well as 6 events from international operating experience (IRS and ICDE) which showed a failure mechanism with special relevance for the post operation phase were identified. The events were presented individually, with special emphasis on the description of the failure mechanism that was particularly relevant for post operation. The failure mechanisms identified can be allocated to the following three general categories: special operating modes; changed operating or ambient conditions; organisational and personnel boundary conditions. The failure mechanisms assigned to these categories are presented in a summarized form and discussed.
Investigation and analysis of hydrogen ignition and explosion events in foreign nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Okuda, Yasunori [Institute of Nuclear Safety System, Inc., Mihama, Fukui (Japan)

2002-09-01

Reports about hydrogen ignition and explosion events in foreign nuclear power plants from 1980 to 2001 were investigated, and 31 events were identified. Analysis showed that they were categorized in (1) outer leakage ignition events and (2) inner accumulation ignition events. The dominant event for PWR (pressurized water reactor) was outer leakage ignition in the main generator, and in BWR (boiling water reactor) it was inner accumulation ignition in the off-gas system. The outer leakage ignition was a result of work process failure with the ignition source, operator error, or main generator hydrogen leakage. The inner accumulation ignition events were caused by equipment failure or insufficient monitoring. With careful preventive measures, the factors leading to these events could be eliminated. (author)
Low-cost failure sensor design and development for water pipeline distribution systems.

Science.gov (United States)

Khan, K; Widdop, P D; Day, A J; Wood, A S; Mounce, S R; Machell, J

2002-01-01

This paper describes the design and development of a new sensor which is low cost to manufacture and install and is reliable in operation with sufficient accuracy, resolution and repeatability for use in newly developed systems for pipeline monitoring and leakage detection. To provide an appropriate signal, the concept of a "failure" sensor is introduced, in which the output is not necessarily proportional to the input, but is unmistakably affected when an unusual event occurs. The design of this failure sensor is based on the water opacity which can be indicative of an unusual event in a water distribution network. The laboratory work and field trials necessary to design and prove out this type of failure sensor are described here. It is concluded that a low-cost failure sensor of this type has good potential for use in a comprehensive water monitoring and management system based on Artificial Neural Networks (ANN).
Giant cardiac fibroma: an unusual cause of failure to thrive.

Science.gov (United States)

Navarini, Susanne; Latzin, Philipp; Kadner, Alexander; Carrel, Thierry; Hutter, Damian

2013-06-01

Cardiac fibromas are extremely rare in the general pediatric population and may present with a wide spectrum of clinical signs, including life-threatening arrhythmias and sudden death. We report a 14-month-old boy who presented with failure to thrive as the only symptom. Echocardiography showed a large cardiac fibroma in the right ventricle. Cardiac magnetic resonance imaging confirmed the diagnosis. After complete surgical tumor resection, the boy showed normal catch-up growth. This case underlines the diversity of clinical features of cardiac tumors, which implies that they should be considered early in the differential diagnosis of infants with failure to thrive.
Fuel element thermo-mechanical analysis during transient events using the FMS and FETMA codes

International Nuclear Information System (INIS)

Hernandez Lopez Hector; Hernandez Martinez Jose Luis; Ortiz Villafuerte Javier

2005-01-01

In the Instituto Nacional de Investigaciones Nucleares of Mexico, the Fuel Management System (FMS) software package has been used for long time to simulate the operation of a BWR nuclear power plant in steady state, as well as in transient events. To evaluate the fuel element thermo-mechanical performance during transient events, an interface between the FMS codes and our own Fuel Element Thermo Mechanical Analysis (FETMA) code is currently being developed and implemented. In this work, the results of the thermo-mechanical behavior of fuel rods in the hot channel during the simulation of transient events of a BWR nuclear power plant are shown. The transient events considered for this work are a load rejection and a feedwater control failure, which among the most important events that can occur in a BWR. The results showed that conditions leading to fuel rod failure at no time appeared for both events. Also, it is shown that a transient due load rejection is more demanding on terms of safety that the failure of a controller of the feedwater. (authors)
Acute Systolic Heart Failure Associated with Complement-Mediated Hemolytic Uremic Syndrome

Directory of Open Access Journals (Sweden)

John L. Vaughn

2015-01-01

Full Text Available Complement-mediated hemolytic uremic syndrome (otherwise known as atypical HUS is a rare disorder of uncontrolled complement activation that may be associated with heart failure. We report the case of a 49-year-old female with no history of heart disease who presented with microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. Given her normal ADAMSTS13 activity, evidence of increased complement activation, and renal biopsy showing evidence of thrombotic microangiopathy, she was diagnosed with complement-mediated HUS. She subsequently developed acute hypoxemic respiratory failure secondary to pulmonary edema requiring intubation and mechanical ventilation. A transthoracic echocardiogram showed evidence of a Takotsubo cardiomyopathy with an estimated left ventricular ejection fraction of 20%, though ischemic cardiomyopathy could not be ruled out. Treatment was initiated with eculizumab. After several failed attempts at extubation, she eventually underwent tracheotomy. She also required hemodialysis to improve her uremia and hypervolemia. After seven weeks of hospitalization and five doses of eculizumab, her renal function and respiratory status improved, and she was discharged in stable condition on room air and independent of hemodialysis. Our case illustrates a rare association between acute systolic heart failure and complement-mediated HUS and highlights the potential of eculizumab in stabilizing even the most critically-ill patients with complement-mediated disease.
Neonatal hemophilia: a rare presentation

Directory of Open Access Journals (Sweden)

Nuno Ferreira

2015-12-01

Full Text Available Hemophilia A is a X-linked hereditary condition that lead to decreased factor VIII activity, occurs mainly in males. Decreased factor VIII activity leads to increased risk of bleeding events. During neonatal period, diagnosis is made after post-partum bleeding complication or unexpected bleeding after medical procedures. Subgaleal hemorrhage during neonatal period is a rare, severe extracranial bleeding with high mortality and usually related to traumatic labor or coagulation disorders. Subgaleal hemorrhage complications result from massive bleeding. We present a neonate with unremarkable family history and uneventful pregnancy with a vaginal delivery with no instrumentation, presenting with severe subgaleal bleeding at 52 hours of life. Aggressive support measures were implemented and bleeding managed. The unexpected bleeding lead to a coagulation study and the diagnosis of severe hemophilia A. There were no known sequelae. This case shows a rare hemophilia presentation reflecting the importance of coagulation studies when faced with unexplained severe bleeding.
Rare cancers are not so rare: The rare cancer burden in Europe

NARCIS (Netherlands)

Gatta, Gemma; van der Zwan, Jan Maarten; Casali, Paolo G.; Siesling, Sabine; Dei Tos, Angelo Paolo; Kunkler, Ian; Otter, Renee; Licitra, Lisa

2011-01-01

Purpose: Epidemiologic information on rare cancers is scarce. The project Surveillance of Rare Cancers in Europe (RARECARE) provides estimates of the incidence, prevalence and survival of rare cancers in Europe based on a new and comprehensive list of these diseases. Materials and methods: RARECARE
Review of failures in nuclear air cleaning systems (1975--1978)

International Nuclear Information System (INIS)

Moeller, D.W.

1979-01-01

During the period from January 1, 1975 through June 30, 1978, over 9,000 Licensee Event Reports (LERs) pertaining to the operation of commercial light water nuclear power plants in the US were reported to the Nuclear Regulatory Commission. Of these reports, over 1,200 (approximately 13%) pertained to failures in air monitoring, ventilating and cleaning systems. For BWR installations, over half of the reported events related to failures in equipment for monitoring the performance of air cleaning systems as contrasted to failures in the systems themselves. In PWR installations, failures in monitoring equipment amounted to about 32% of the total. Reported problem areas in BWR installations included the primary containment and standby gas treatment and off-gas systems, as well as the High Pressure Coolant Injection and Reactor Core Isolation Systems. For PWR installations, reported problem areas included primary containment and associated spray systems and waste processing equipment. Although data on reported failures in power reactor installations can be interpreted in a variety of ways, one message is clear. There is a need for research on the development of more reliable equipment for sampling and monitoring air systems. Equipment that provides inaccurate data on the performance of such systems can lead to as many problems as inadequacies in the systems themselves
Case report: Management of severe posterior open bite due to primary failure of eruption.

LENUS (Irish Health Repository)

Mc Cafferty, J

2010-06-01

Primary failure of tooth eruption (PFE) is a rare condition affecting any or all posterior quadrants. Unilateral involvement of maxillary and mandibular quadrants causes a dramatic posterior open bite that requires complex management strategies.
Overview of AEOD's program for trending reactor operational events

International Nuclear Information System (INIS)

Baranowsky, P.W.; O'Reilly, P.D.; Rasmuson, D.M.; Houghton, J.R.

1994-01-01

This paper presents an overview of the trending program being performed by AEOD. The major elements of the program include: (1) system and component reliability trending and analysis, (2) special data collection and analysis (e.g., IPE and PRA component failure data, common cause failure event data), (3) risk assessment of safety issues based on actual operating experience, (4) Accident Sequence Precursor (ASP) Program, and (5) trending US industry risk. AEOD plans to maintain up-to-date safety data trends for selected high risk or high regulatory profile components, systems, accident initiators, accident sequences, and regulatory issues. AEOD will also make greater use of PRA insights and perform limited probabilistic safety assessments to evaluate the safety significance of qualitative results. Examples of a system study and an issue evaluation are presented, as well as a summary of the common cause failure event database
The role of levosimendan in acute heart failure complicating acute coronary syndrome

DEFF Research Database (Denmark)

Nieminen, Markku S; Buerke, M.; Cohen-Solal, A.

2016-01-01

Acute heart failure and/or cardiogenic shock are frequently triggered by ischemic coronary events. Yet, there is a paucity of randomized data on the management of patients with heart failure complicating acute coronary syndrome, as acute coronary syndrome and cardiogenic shock have frequently bee...
neutron-Induced Failures in semiconductor Devices

Energy Technology Data Exchange (ETDEWEB)

Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-13

Single Event Effects are a very significant failure mode in modern semiconductor devices that may limit their reliability. Accelerated testing is important for semiconductor industry. Considerable more work is needed in this field to mitigate the problem. Mitigation of this problem will probably come from Physicists and Electrical Engineers working together
Toluene inducing acute respiratory failure in a spray paint sniffer.

Science.gov (United States)

Peralta, Diego P; Chang, Aymara Y

2012-01-01

Toluene, formerly known as toluol, is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent. Like other solvents, toluene is sometimes also used as an inhalant drug for its intoxicating properties. It has potential to cause multiple effects in the body including death. I report a case of a 27-year-old male, chronic spray paint sniffer, who presented with severe generalized muscle weakness and developed acute respiratory failure requiring ventilatory support. Toluene toxicity was confirmed with measurement of hippuric acid of 8.0 g/L (normal <5.0 g/L). Acute respiratory failure is a rare complication of chronic toluene exposure that may be lethal if it is not recognized immediately. To our knowledge, this is the second case of acute respiratory failure due to toluene exposure.
Elastic Rock Heterogeneity Controls Brittle Rock Failure during Hydraulic Fracturing

Science.gov (United States)

Langenbruch, C.; Shapiro, S. A.

2014-12-01

For interpretation and inversion of microseismic data it is important to understand, which properties of the reservoir rock control the occurrence probability of brittle rock failure and associated seismicity during hydraulic stimulation. This is especially important, when inverting for key properties like permeability and fracture conductivity. Although it became accepted that seismic events are triggered by fluid flow and the resulting perturbation of the stress field in the reservoir rock, the magnitude of stress perturbations, capable of triggering failure in rocks, can be highly variable. The controlling physical mechanism of this variability is still under discussion. We compare the occurrence of microseismic events at the Cotton Valley gas field to elastic rock heterogeneity, obtained from measurements along the treatment wells. The heterogeneity is characterized by scale invariant fluctuations of elastic properties. We observe that the elastic heterogeneity of the rock formation controls the occurrence of brittle failure. In particular, we find that the density of events is increasing with the Brittleness Index (BI) of the rock, which is defined as a combination of Young's modulus and Poisson's ratio. We evaluate the physical meaning of the BI. By applying geomechanical investigations we characterize the influence of fluctuating elastic properties in rocks on the probability of brittle rock failure. Our analysis is based on the computation of stress fluctuations caused by elastic heterogeneity of rocks. We find that elastic rock heterogeneity causes stress fluctuations of significant magnitude. Moreover, the stress changes necessary to open and reactivate fractures in rocks are strongly related to fluctuations of elastic moduli. Our analysis gives a physical explanation to the observed relation between elastic heterogeneity of the rock formation and the occurrence of brittle failure during hydraulic reservoir stimulations. A crucial factor for understanding
Common Cause Failure Analysis for the Digital Plant Protection System

International Nuclear Information System (INIS)

Kagn, Hyun Gook; Jang, Seung Cheol

2005-01-01

Safety-critical systems such as nuclear power plants adopt the multiple-redundancy design in order to reduce the risk from the single component failure. The digitalized safety-signal generation system is also designed based on the multiple-redundancy strategy which consists of more redundant components. The level of the redundant design of digital systems is usually higher than those of conventional mechanical systems. This higher redundancy would clearly reduce the risk from the single failure of components, but raise the importance of the common cause failure (CCF) analysis. This research aims to develop the practical and realistic method for modeling the CCF in digital safety-critical systems. We propose a simple and practical framework for assessing the CCF probability of digital equipment. Higher level of redundancy causes the difficulty of CCF analysis because it results in impractically large number of CCF events in the fault tree model when we use conventional CCF modeling methods. We apply the simplified alpha-factor (SAF) method to the digital system CCF analysis. The precedent study has shown that SAF method is quite realistic but simple when we consider carefully system success criteria. The first step for using the SAF method is the analysis of target system for determining the function failure cases. That is, the success criteria of the system could be derived from the target system's function and configuration. Based on this analysis, we can calculate the probability of single CCF event which represents the CCF events resulting in the system failure. In addition to the application of SAF method, in order to accommodate the other characteristics of digital technology, we develop a simple concept and several equations for practical use

A rare case of lymphangioleiomyomatosis with recurrent pneumothorax

Directory of Open Access Journals (Sweden)

Vinay Mahishale

2015-01-01

Full Text Available Lymphangioleiomyomatosis (LAM is a rare disease of unknown etiology that traditionally affects young women of childbearing or premenopausal age. It is characterized by proliferation of atypical smooth muscle cells, preferentially along bronchovascular structures that cause progressive respiratory failure. Owing to its unusual and nonspecific presenting symptoms, patients often receive missed or delayed diagnosis. This disease occurs sporadically or in association with the genetic disease-tuberous sclerosis complex. Recurrent pneumothorax is the hallmark of LAM. We present a 16-year-old young female having recurrent pneumothorax with LAM.
An atypical presentation of mechanical failure of eruption of a mandibular permanent molar: diagnosis and treatment case report.

LENUS (Irish Health Repository)

Smith, C P

2012-06-01

Failure of eruption of mandibular permanent molars occurs infrequently but is a difficult clinical problem. It can be due to local or systemic factors or failure of the eruption process. Primary failure of eruption (PFE) is a rare condition that can result in severe posterior open bite, requires complex treatment strategies and has unfavourable outcomes. Mechanical failure of eruption (MFE) is more unusual but can respond positively to treatment. Differentiating between the two is crucial in making the correct diagnosis and managing the case successfully.
Metastatic Choriocarcinoma Following Live Birth – A Rare Presentation

Directory of Open Access Journals (Sweden)

Joya Sree Roy

2011-09-01

Full Text Available Choriocarcinoma is the most malignant tumor of gestational trophoblastic neoplasia. Post-partum choriocarcinoma is an infrequent event with poor prognosis. The diagnosis is usually delayed due to failure to recognize the mode of presentation of this disease. Being a rare occurrence, limited data is available regarding its clinical features. We present a 24 years old women with parity one delivered by caesarean section indicated for premature rupture of membrane with fetal distress at 39 wks of pregnancy. Frequent episodes of heavy vaginal bleeding had started 28 days following C/S. For this, she had H/O uterine evacuatin twice within 5 days interval. Biopsy report of second curettage showed choriocarcinoma. On admission to Dhaka Medical College Hospital (DMCH, the pretreatment Human Chorionic Gonadotrophin (βhCG level was >200000.0 IU/L, uterine mass of about 18 wks pregnancy size & X-Ray chest showed segmental consolidation in left mid zone of lung. After consultation with oncologist Etoposide, Methotrexate, Dactinomycin, Cyclophosphamide & Vincristine (EMACO therapy was started but before completion of her proposed cycles, she developed a live threatening condition which was managed very urgently and meticulously. Now the patient is under regular monitoring. Key words: GTD; Choriocarcinoma DOI: http://dx.doi.org/10.3329/bsmmuj.v4i2.8642 BSMMU J 2011; 4(2:116-118
A Rare Occurance with Epidermolysis Bullosa Disease: Dilated Cardiomyopathy

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Derya Cimen

2014-02-01

Full Text Available Epidermolysis bullosa is a congenital and herediter vesiculobullous disease. Dystrophic form of this disease is characterized by severe malnutrition, failure to thrive, adhesions at fingers, joint contractures related with the formation of scar tissues, carcinoma of the skin, anemia, hipoalbuminemia, wound enfections and sepsis. Rarely, mortal dilated cardiomyopathy may occur in patients. In this report we present a 13 year-old pediatric patient with dilated cardiomyopathy, clinically diagnosed with Epidermolysis bullosa as well as a review of recent related literature.
Mammographic and sonographic findings of unilateral breast edema in congestive heart failure : a case report

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Kyung; Lee, Seung Koo; Oh, Ki Keun [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

1997-06-01

Unilateral breast edema has many causes, though among these, congestive heart failure is rare. We report mammographic and sonographic findings of unilateral breast edema due to congestive heart failure. Mammography showed diffuse increase density and skin thickening but no evidence of mass or calcification. Ultrasonography showed skin thickening and increased echogenicity in the subcutaneous fat layer, while in the dermal layer, with tubular and reticular anechoic structures suggestive of dilated lymphatics were seen. After treatment of the heart failure, resolution of the abnormalities seen on mammogram established that these were secondary findings.
Mammographic and sonographic findings of unilateral breast edema in congestive heart failure : a case report

International Nuclear Information System (INIS)

Kim, Eun Kyung; Lee, Seung Koo; Oh, Ki Keun

1997-01-01

Unilateral breast edema has many causes, though among these, congestive heart failure is rare. We report mammographic and sonographic findings of unilateral breast edema due to congestive heart failure. Mammography showed diffuse increase density and skin thickening but no evidence of mass or calcification. Ultrasonography showed skin thickening and increased echogenicity in the subcutaneous fat layer, while in the dermal layer, with tubular and reticular anechoic structures suggestive of dilated lymphatics were seen. After treatment of the heart failure, resolution of the abnormalities seen on mammogram established that these were secondary findings
Genomic analysis and selected molecular pathways in rare cancers

International Nuclear Information System (INIS)

Liu, Stephen V; Lenkiewicz, Elizabeth; Evers, Lisa; Holley, Tara; Kiefer, Jeffrey; Demeure, Michael J; Ramanathan, Ramesh K; Von Hoff, Daniel D; Barrett, Michael T; Ruiz, Christian; Glatz, Katharina; Bubendorf, Lukas; Eng, Cathy

2012-01-01

It is widely accepted that many cancers arise as a result of an acquired genomic instability and the subsequent evolution of tumor cells with variable patterns of selected and background aberrations. The presence and behaviors of distinct neoplastic cell populations within a patient's tumor may underlie multiple clinical phenotypes in cancers. A goal of many current cancer genome studies is the identification of recurring selected driver events that can be advanced for the development of personalized therapies. Unfortunately, in the majority of rare tumors, this type of analysis can be particularly challenging. Large series of specimens for analysis are simply not available, allowing recurring patterns to remain hidden. In this paper, we highlight the use of DNA content-based flow sorting to identify and isolate DNA-diploid and DNA-aneuploid populations from tumor biopsies as a strategy to comprehensively study the genomic composition and behaviors of individual cancers in a series of rare solid tumors: intrahepatic cholangiocarcinoma, anal carcinoma, adrenal leiomyosarcoma, and pancreatic neuroendocrine tumors. We propose that the identification of highly selected genomic events in distinct tumor populations within each tumor can identify candidate driver events that can facilitate the development of novel, personalized treatment strategies for patients with cancer. (paper)
Tumoral calcinosis in a dog with chronic renal failure : clinical communication

Directory of Open Access Journals (Sweden)

T.C. Spotswood

2003-06-01

Full Text Available A 2-year-old male German shepherd dog in poor bodily condition was evaluated for thoracic limb lameness due to a large, firm mass medial to the left cranial scapula. Radiography revealed several large cauliflower-like mineralized masses in the craniomedial left scapula musculature, pectoral region and bilaterally in the biceps tendon sheaths. Urinalysis, haematology and serum biochemistry showed that the dog was severely anaemic, hyperphosphataemic and in chronic renal failure. The dog was euthanased and a full post mortem performed. A diagnosis of chronic renal failure with secondary hyperparathyroidism was confirmed. The mineralized masses were grossly and histopathologically consistent with a diagnosis of tumoral calcinosis. Tumoral calcinosis associated with chronic renal failure that does not involve the foot pads is rarely seen.
A secure distributed logistic regression protocol for the detection of rare adverse drug events.

Science.gov (United States)

El Emam, Khaled; Samet, Saeed; Arbuckle, Luk; Tamblyn, Robyn; Earle, Craig; Kantarcioglu, Murat

2013-05-01

There is limited capacity to assess the comparative risks of medications after they enter the market. For rare adverse events, the pooling of data from multiple sources is necessary to have the power and sufficient population heterogeneity to detect differences in safety and effectiveness in genetic, ethnic and clinically defined subpopulations. However, combining datasets from different data custodians or jurisdictions to perform an analysis on the pooled data creates significant privacy concerns that would need to be addressed. Existing protocols for addressing these concerns can result in reduced analysis accuracy and can allow sensitive information to leak. To develop a secure distributed multi-party computation protocol for logistic regression that provides strong privacy guarantees. We developed a secure distributed logistic regression protocol using a single analysis center with multiple sites providing data. A theoretical security analysis demonstrates that the protocol is robust to plausible collusion attacks and does not allow the parties to gain new information from the data that are exchanged among them. The computational performance and accuracy of the protocol were evaluated on simulated datasets. The computational performance scales linearly as the dataset sizes increase. The addition of sites results in an exponential growth in computation time. However, for up to five sites, the time is still short and would not affect practical applications. The model parameters are the same as the results on pooled raw data analyzed in SAS, demonstrating high model accuracy. The proposed protocol and prototype system would allow the development of logistic regression models in a secure manner without requiring the sharing of personal health information. This can alleviate one of the key barriers to the establishment of large-scale post-marketing surveillance programs. We extended the secure protocol to account for correlations among patients within sites through
Dependency Analysis Guidance Nordic/German Working Group on Common Cause Failure analysis. Phase 2, Development of Harmonized Approach and Applications for Common Cause Failure Quantification

Energy Technology Data Exchange (ETDEWEB)

Becker, Guenter; Johanson, Gunnar; Lindberg, Sandra; Vaurio, Jussi

2009-03-15

The Regulatory Code SSMFS 2008:1 of Swedish Radiation Safety Authority (SSM) includes requirements regarding the performance of probabilistic safety assessments (PSA), as well as PSA activities in general. Therefore, the follow-up of these activities is part of the inspection tasks of SSM. According to the SSMFS 2008:1, the safety analyses shall be based on a systematic identification and evaluation of such events, event sequences and other conditions which may lead to a radiological accident. The research report Nordic/German Working Group on Common cause Failure analysis. Phase 2 project report: Development of Harmonized Approach and Applications for Common Cause Failure Quantification has been developed under a contract with the Nordic PSA Group (NPSAG) and its German counterpart VGB, with the aim to create a common experience base for defence and analysis of dependent failures i.e. Common Cause Failures CCF. Phase 2 in this project if a deepened data analyses of CCF events and a demonstration on how the so called impact vectors can be constructed and on how CCF parameters are estimated. The word Guidance in the report title is used in order to indicate a common methodological guidance accepted by the NPSAG, based on current state of the art concerning the analysis of dependent failures and adapted to conditions relevant for Nordic sites. This will make it possible for the utilities to perform cost effective improvements and analyses. The report presents a common attempt by the authorities and the utilities to create a methodology and experience base for defence and analysis of dependent failures. The performed benchmark application has shown how important the interpretation of base data is to obtain robust CCF data and data analyses results. Good features were found in all benchmark approaches. The obtained experiences and approaches should now be used in harmonised procedures. A next step could be to develop and agree on event and formula driven impact vector
Dependency Analysis Guidance Nordic/German Working Group on Common Cause Failure analysis. Phase 2, Development of Harmonized Approach and Applications for Common Cause Failure Quantification

International Nuclear Information System (INIS)

Becker, Guenter; Johanson, Gunnar; Lindberg, Sandra; Vaurio, Jussi

2009-03-01

The Regulatory Code SSMFS 2008:1 of Swedish Radiation Safety Authority (SSM) includes requirements regarding the performance of probabilistic safety assessments (PSA), as well as PSA activities in general. Therefore, the follow-up of these activities is part of the inspection tasks of SSM. According to the SSMFS 2008:1, the safety analyses shall be based on a systematic identification and evaluation of such events, event sequences and other conditions which may lead to a radiological accident. The research report Nordic/German Working Group on Common cause Failure analysis. Phase 2 project report: Development of Harmonized Approach and Applications for Common Cause Failure Quantification has been developed under a contract with the Nordic PSA Group (NPSAG) and its German counterpart VGB, with the aim to create a common experience base for defence and analysis of dependent failures i.e. Common Cause Failures CCF. Phase 2 in this project if a deepened data analyses of CCF events and a demonstration on how the so called impact vectors can be constructed and on how CCF parameters are estimated. The word Guidance in the report title is used in order to indicate a common methodological guidance accepted by the NPSAG, based on current state of the art concerning the analysis of dependent failures and adapted to conditions relevant for Nordic sites. This will make it possible for the utilities to perform cost effective improvements and analyses. The report presents a common attempt by the authorities and the utilities to create a methodology and experience base for defence and analysis of dependent failures. The performed benchmark application has shown how important the interpretation of base data is to obtain robust CCF data and data analyses results. Good features were found in all benchmark approaches. The obtained experiences and approaches should now be used in harmonised procedures. A next step could be to develop and agree on event and formula driven impact vector
When things go wrong: how health care organizations deal with major failures.

Science.gov (United States)

Walshe, Kieran; Shortell, Stephen M

2004-01-01

Concern about patient safety, caused in part by high-profile major failures in which many patients have been harmed, is rising worldwide. This paper draws on examples of such failures from several countries to analyze how these events are dealt with and to identify lessons and recommendations for policy. Better systems are needed for reporting and investigating failures and for implementing the lessons learned. The culture of secrecy, professional protectionism, defensiveness, and deference to authority is central to such major failures, and preventing future failures depends on cultural as much as structural change in health care systems and organizations.
Psychosocial risk factors and heart failure hospitalization: a prospective cohort study

DEFF Research Database (Denmark)

Rod, Naja Hulvej; Andersen, Ingelise; Prescott, Eva

2011-01-01

,670 participants of the Copenhagen City Heart Study (Denmark) were asked comprehensive questions on major life events, work-related stress, social network, vital exhaustion, and sleep medication and were followed in nationwide registries until 2007, with less than 0.2% loss to follow-up. Almost one......Prospective studies on the role of psychosocial factors in heart failure development are virtually nonexistent. The authors aimed to address the effect of psychosocial factors on the risk of heart failure hospitalization in men and women free of cardiovascular disease. In 1991-1993, the 8...... interval: 1.20, 3.10) and women (hazard ratio = 2.56, 95% confidence interval: 1.80, 3.65). Contrary to expectation, major life events, social network, and sleeping medication did not play an individual role for heart failure hospitalization. Because of the high prevalence of vital exhaustion...
Association between large strongyle genera in larval cultures--using rare-event poisson regression.

Science.gov (United States)

Cao, X; Vidyashankar, A N; Nielsen, M K

2013-09-01

Decades of intensive anthelmintic treatment has caused equine large strongyles to become quite rare, while the cyathostomins have developed resistance to several drug classes. The larval culture has been associated with low to moderate negative predictive values for detecting Strongylus vulgaris infection. It is unknown whether detection of other large strongyle species can be statistically associated with presence of S. vulgaris. This remains a statistical challenge because of the rare occurrence of large strongyle species. This study used a modified Poisson regression to analyse a dataset for associations between S. vulgaris infection and simultaneous occurrence of Strongylus edentatus and Triodontophorus spp. In 663 horses on 42 Danish farms, the individual prevalences of S. vulgaris, S. edentatus and Triodontophorus spp. were 12%, 3% and 12%, respectively. Both S. edentatus and Triodontophorus spp. were significantly associated with S. vulgaris infection with relative risks above 1. Further, S. edentatus was associated with use of selective therapy on the farms, as well as negatively associated with anthelmintic treatment carried out within 6 months prior to the study. The findings illustrate that occurrence of S. vulgaris in larval cultures can be interpreted as indicative of other large strongyles being likely to be present.
OBSTETRIC RENAL FAILURE

Directory of Open Access Journals (Sweden)

Rajeshwari

2015-11-01

Full Text Available Renal failure in obstetrics is rare but important complication, associated with significant mortality and long term morbidity.1,2 It includes acute renal failure due to obstetrical complications or due to deterioration of existing renal disease. AIMS AND OBJECTIVES: To evaluate the etiology and outcome of renal failure in obstetric patients. METHODS: We prospectively analyzed 30 pregnant and puerperal women with acute renal failure or pre-existing renal disease developing renal failure during pregnancy between November 2007 to sep-2009. Patients who presented/developed ARF during the hospital stay were included in this study. RESULTS: Among 30 patients, mean age was 23 years and 33 years age group. 12 cases (40% patients were primigravidae and 9(30% patients were multigravidae and 9 cases (30% presented in post-partum period. Eighteen cases (60% with ARF were seen in third trimester, followed by in postpartum period 9 cases (30%. Most common contributing factors to ARF were Pre-eclampsia, eclampsia and HELLP syndrome 60%, sepsis 56.6%, post abortal ARF 10%. DIC 40%. Haemorrhage as the aetiology for ARF was present 46%, APH in 20% and PPH in 26.6%. The type of ARF was renal in (63% and prerenal (36%; Oliguric seen in 10 patients (33% and high mortality (30%. Among the 20 pregnant patients with ARF, The average period of gestation was 33±2 weeks (30 -36 weeks, 5 cases (25% presented with intrauterine fetal demise and 18 cases (66% had preterm vaginal delivery and 2 cases (10% had induced abortion. And the average birth weight was 2±0.5 kg (1.5 kg. Eight cases (26% required dialysis. 80% of patients recovered completely of renal functions. 63% patients recovered without renal replacement therapy whereas 17% required dialysis. the maternal mortality was 20%, the main reason for mortality was septic shock and multi organ dysfunction (66%. CONCLUSION: ARF related pregnancy was seen commonly in the primigravidae and in the third trimester, the most
Operational failure at the Paks Nuclear Power Plant

International Nuclear Information System (INIS)

Szatmary, Z.

2003-01-01

NPP failures are ranked according to the International Nuclear Event Scale. To rank the failure first a presentation of the pressurized water plant is given, including fuel change, maintenance cleaning and decontamination process. The failure has been produced with fuel bars in the cleaning container. Consequences of the failure are small, negligible environmental pollution with radioactive material and significant financial outfall due to inactivity of block 2. Among the causes of the failure are design errors of the cleaning container, the pure chemical approach to cleaning, unknown risk factors for some of the cleaning staff, cleaning container has not been verified and approved by responsible authorities, the prevalence of economic and quantitative indicators of the plant on the detriment of safety. Organisational factors also contribute to the possibility of nuclear failures. Specialist training in Germany (where the container has been produced) is significantly reduced, while in Hungary the political tide has caused a permanent change in the higher echelons of the plant management, where nuclear specialists were not included. (Gy.M.)
A rare cause of osteonecrosis

Directory of Open Access Journals (Sweden)

Paolo Agostinis

2012-01-01

Full Text Available IntroductionHereditary hemochromatosis (HH is an autosomal recessive disorder caused by mutations in the HFE gene, which increase intestinal iron absorption. The prevalence of C282Y homozygosity, which causes the disorder, is 0.5% in Caucasian populations. The clinical manifestations are related to excess iron in the tissues, especially the liver, heart, pancreas, pituitary, and skin. They include fatigue, loss of libido or impotence in males, liver disease, skin pigmentation, diabetes mellitus, cardiac enlargement—with or without heart failure, and conduction defects. The classic triad of cirrhosis, diabetes mellitus, and skin pigmentation (“bronze diabetes” results from a combination of iron deposits and melanin. It occurs late in the disease, when the total body iron content is more than five times the normal value, about 20 grams. Left untreated, approximately half of all patients with HH eventually develop arthralgia or arthropathy. Chondrocalcinosis, chronic pseudo-osteoarthritis, and osteoporosis are the major rheumatic manifestations of HH. The cause of the arthropathy is still unknown. Iron deposits within joints may trigger a number of pathologic events, such as free radical generation and crystal deposition, which stimulate immune complex formation and inflammation.Materials and methodsWe describe the case of a 48-year-old male suffering from chronic bilateral ankle pain.ResultsThe work-up revealed osteonecrosis of ankle. The patient also presented high plasma ferritin levels and homozygosity for the C282Y mutation. Other than HH, which was confirmed by liver biopsy, the patient had no other risk factors for osteonecrosis.DiscussionHH represents a rare cause of osteonecrosis, and there are no prior reports of aseptic osteonecrosis of the ankle in a patient with this disease. The pathogenetic mechanism remains unknown.
Rapid reversal of heart failure in a patient with pheochromocytoma and catecholamine-induced myocarditis/cardiomyopathy

International Nuclear Information System (INIS)

Ahmed, I.; Sankaran, R.; Al-Addad, A.

2002-01-01

Pheochromocytoma is rare and usually presents as paroxysal or sustained hypertension, nonetheless, it can also cause severe acute pulmonary edema in normotensive individuals. We present a case with pheochromocytoma and severe left ventricular failure caused by catecholamine induced myocarditis/cardiomyopathy. Severe left ventricular failure resolved rapidly and left ventricular systolic function became normal within two weeks of medical treatment. Later, patient underwent elective and uneventful surgical removal of pheochromocytoma. (author)
A Fourier analysis of extreme events

DEFF Research Database (Denmark)

Mikosch, Thomas Valentin; Zhao, Yuwei

2014-01-01

The extremogram is an asymptotic correlogram for extreme events constructed from a regularly varying stationary sequence. In this paper, we define a frequency domain analog of the correlogram: a periodogram generated from a suitable sequence of indicator functions of rare events. We derive basic ...... properties of the periodogram such as the asymptotic independence at the Fourier frequencies and use this property to show that weighted versions of the periodogram are consistent estimators of a spectral density derived from the extremogram....
Reporting of safeguards events

International Nuclear Information System (INIS)

Dwyer, P.A.; Ervin, N.E.

1988-02-01

On June 9, 1987, the Commission published in the Federal Register a final rule revising the reporting requirements for safeguards events. Safeguards events include actual or attempted theft of special nuclear material (SNM); actual or attempted acts or events which interrupt normal operations at power reactors due to unauthorized use of or tampering with machinery, components, or controls; certain threats made against facilities possessing SNM; and safeguards system failures impacting the effectiveness of the system. The revised rule was effective October 8, 1987. On September 14, 1987, the NRC held a workshop in Bethesda, MD, to answer affected licensees' questions on the final rule. This report documents questions discussed at the September 14 meeting, reflects a completed staff review of the answers, and supersedes previous oral comment on the topics covered

A method to assign failure rates for piping reliability assessments

International Nuclear Information System (INIS)

Gamble, R.M.; Tagart, S.W. Jr.

1991-01-01

This paper reports on a simplified method that has been developed to assign failure rates that can be used in reliability and risk studies of piping. The method can be applied on a line-by-line basis by identifying line and location specific attributes that can lead to piping unreliability from in-service degradation mechanisms and random events. A survey of service experience for nuclear piping reliability also was performed. The data from this survey provides a basis for identifying in-service failure attributes and assigning failure rates for risk and reliability studies
A Novel RSPF Approach to Prediction of High-Risk, Low-Probability Failure Events

Data.gov (United States)

National Aeronautics and Space Administration — Particle filters (PF) have been established as the de facto state of the art in failure prognosis, and particularly in the representation and management of...
A Rare Case Report of Immobility-Induced Hypercalcemia in an Infant.

Science.gov (United States)

Vyas, Neha; Kaminski, Beth; MacLeish, Sarah

2016-04-01

Immobility-induced hypercalcemia is a rare cause of hypercalcemia in children, and to our knowledge it has never been reported in an infant. Infants and children are in a state of high bone turnover. Therefore, they are prone to the imbalance of osteoblastic and osteoclastic activity that occurs with prolonged immobilization, leading to hypercalcemia. Here we present the case of an infant with hypercalcemia who presented with fatigue, irritability, and failure to thrive after prolonged immobilization. Therapeutic interventions were conservative and included hydration and increased mobility leading to complete resolution. This case highlights the importance of including this rare entity in a differential diagnosis of hypercalcemia as well as screening postsurgical patients with prolonged immobility for hypercalcemia. Copyright © 2016 by the American Academy of Pediatrics.
Structuring free form verbal descriptions in equipment failure reports

International Nuclear Information System (INIS)

Huzdovich, J.

1983-01-01

Information is encoded for convenience in computer sort/search routines used to manage a large number of records. The codes in use for equipment failure reports are limited due to practical considerations, and this limitation forces the reporter to leave out information to satisfy the coding requirements. The free form verbal descriptions, as found in the Generating Availability Data System (GADS) and the Nuclear Plant Reliability Data System (NPRDS), allow for reporting of this non-codable information. A systematic approach to constructing the verbal description based on rules of grammar, especially syntax, results in a structured narrative suitable for computer data management schemes. In addition, the reporter has a full range of descriptive terminology and does not have to select subjectively from a predetermined, limited vocabulary to describe the event. This paper introduces a concept that places in perspective the integration of structured, formal reporting and free form verbal description. A second benefit of this structured narrative is the systematic development of failure mode/failure cause relationships in the event
TUF simulation of Darlington class IV power failure

Energy Technology Data Exchange (ETDEWEB)

Liauw, W K; Liu, W S; Leung, R K; Phillips, B S [Ontario Hydro, Toronto, ON (Canada)

1996-12-31

Presented here is the TUF simulation of the initial transient of the Class IV power failure event that occurred on November 25, 1993 at Darlington Unit 4. The important physical parameters and models that relate to this event are discussed. The agreements between the code predictions and the plant data on the thermal-hydraulics and controller responses demonstrate the code reliability for plant operational support. (author). 4 refs., 1 tab., 12 figs.
TUF simulation of Darlington class IV power failure

International Nuclear Information System (INIS)

Liauw, W.K.; Liu, W.S.; Leung, R.K.; Phillips, B.S.

1995-01-01

Presented here is the TUF simulation of the initial transient of the Class IV power failure event that occurred on November 25, 1993 at Darlington Unit 4. The important physical parameters and models that relate to this event are discussed. The agreements between the code predictions and the plant data on the thermal-hydraulics and controller responses demonstrate the code reliability for plant operational support. (author). 4 refs., 1 tab., 12 figs
Image and Substance Failures in Regional Organisations: Causes, Consequences, Learning and Change?

Directory of Open Access Journals (Sweden)

Meng Hsuan Chou

2016-08-01

Full Text Available States often pool their sovereignty, capacity and resources to provide regionally specific public goods, such as security or trade rules, and regional organisations play important roles in international relations as institutions that attempt to secure peace and contribute to achieving other similar global policy goals. We observe failures occurring in these arrangements and activities in two areas: substance and image. To analytically account for this, we distinguish four modes of substance and image change and link these to specific types of failure and (lack of learning. To empirically ground and test our assumptions, we examine instances of image failure in ASEAN (political/security policy and substantive policy failure in EU labour migration policy. In so doing, this article contributes to several different fields of study and concepts that have hitherto rarely engaged with one another: analyses of policy failure from public policy, and regional integration concerns from area studies and international relations. We conclude with suggestions for ways forward to further analyse and understand failures at the international and supranational levels.
A Case Report Describing a Rare Presentation of Simultaneous Occurrence of MPO-ANCA-Associated Vasculitis and Rheumatoid Arthritis.

Science.gov (United States)

Foray, Nathalie; Hudali, Tamer; Papireddy, Muralidhar; Gao, John

2016-01-01

Background . Renal-limited myeloperoxidase vasculitis with simultaneous rheumatoid arthritis is reported as a rare occurrence. Review of literature suggests that most patients had a diagnosis of rheumatoid arthritis for several years prior to presenting with renal failure from myeloperoxidase vasculitis. Case Presentation . A 58-year-old Caucasian male presented to the hospital experiencing malaise, fevers, decreased oral intake, nausea, and vomiting for one week duration. His past medical history consisted of newly diagnosed but untreated rheumatoid arthritis, hypertension, and non-insulin-dependent diabetes mellitus. He was found to have acute renal failure, proteinuria, and hypoglycemia. Standard therapy, including intravenous fluids, did not improve his acute renal failure. A vasculitis workup resulted in a positive myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA). Renal biopsy revealed crescentic glomerulonephritis (GN) pauci-immune type, suggestive of MPO-ANCA-associated vasculitis (MPO-AAV). Treatment consisted of prednisone, cyclophosphamide, and seven cycles of plasmapheresis, in addition to hemodialysis for uremia. Upon discharge, he received hemodialysis for another week and continued treatment with cyclophosphamide and prednisone. Conclusion . Patients with longstanding rheumatoid arthritis may develop renal failure due to nonsteroidal anti-inflammatory medication use and AA type amyloidosis; however, necrotizing glomerulonephritis with crescent formation has been rarely reported. This stresses the importance of early recognition and swift initiation of treatment.
A Case Report Describing a Rare Presentation of Simultaneous Occurrence of MPO-ANCA-Associated Vasculitis and Rheumatoid Arthritis

Directory of Open Access Journals (Sweden)

Nathalie Foray

2016-01-01

Full Text Available Background. Renal-limited myeloperoxidase vasculitis with simultaneous rheumatoid arthritis is reported as a rare occurrence. Review of literature suggests that most patients had a diagnosis of rheumatoid arthritis for several years prior to presenting with renal failure from myeloperoxidase vasculitis. Case Presentation. A 58-year-old Caucasian male presented to the hospital experiencing malaise, fevers, decreased oral intake, nausea, and vomiting for one week duration. His past medical history consisted of newly diagnosed but untreated rheumatoid arthritis, hypertension, and non-insulin-dependent diabetes mellitus. He was found to have acute renal failure, proteinuria, and hypoglycemia. Standard therapy, including intravenous fluids, did not improve his acute renal failure. A vasculitis workup resulted in a positive myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA. Renal biopsy revealed crescentic glomerulonephritis (GN pauci-immune type, suggestive of MPO-ANCA-associated vasculitis (MPO-AAV. Treatment consisted of prednisone, cyclophosphamide, and seven cycles of plasmapheresis, in addition to hemodialysis for uremia. Upon discharge, he received hemodialysis for another week and continued treatment with cyclophosphamide and prednisone. Conclusion. Patients with longstanding rheumatoid arthritis may develop renal failure due to nonsteroidal anti-inflammatory medication use and AA type amyloidosis; however, necrotizing glomerulonephritis with crescent formation has been rarely reported. This stresses the importance of early recognition and swift initiation of treatment.
SIMULATED HUMAN ERROR PROBABILITY AND ITS APPLICATION TO DYNAMIC HUMAN FAILURE EVENTS

Energy Technology Data Exchange (ETDEWEB)

Herberger, Sarah M.; Boring, Ronald L.

2016-10-01

Abstract Objectives: Human reliability analysis (HRA) methods typically analyze human failure events (HFEs) at the overall task level. For dynamic HRA, it is important to model human activities at the subtask level. There exists a disconnect between dynamic subtask level and static task level that presents issues when modeling dynamic scenarios. For example, the SPAR-H method is typically used to calculate the human error probability (HEP) at the task level. As demonstrated in this paper, quantification in SPAR-H does not translate to the subtask level. Methods: Two different discrete distributions were generated for each SPAR-H Performance Shaping Factor (PSF) to define the frequency of PSF levels. The first distribution was a uniform, or uninformed distribution that assumed the frequency of each PSF level was equally likely. The second non-continuous distribution took the frequency of PSF level as identified from an assessment of the HERA database. These two different approaches were created to identify the resulting distribution of the HEP. The resulting HEP that appears closer to the known distribution, a log-normal centered on 1E-3, is the more desirable. Each approach then has median, average and maximum HFE calculations applied. To calculate these three values, three events, A, B and C are generated from the PSF level frequencies comprised of subtasks. The median HFE selects the median PSF level from each PSF and calculates HEP. The average HFE takes the mean PSF level, and the maximum takes the maximum PSF level. The same data set of subtask HEPs yields starkly different HEPs when aggregated to the HFE level in SPAR-H. Results: Assuming that each PSF level in each HFE is equally likely creates an unrealistic distribution of the HEP that is centered at 1. Next the observed frequency of PSF levels was applied with the resulting HEP behaving log-normally with a majority of the values under 2.5% HEP. The median, average and maximum HFE calculations did yield
Scrub typhus causing neonatal hepatitis with acute liver failure-A case series.

Science.gov (United States)

Vajpayee, Shailja; Gupta, R K; Gupta, M L

2017-05-01

Neonatal hepatitis with acute liver failure due to varied etiology including various infections is reported in the past. Scrub typhus as a cause of neonatal hepatitis has rarely been reported in literature. A high index of clinical suspicion is required for early diagnosis and timely treatment. Severity and prognosis of the disease varies widely because several different strains of Orientia tsutsugamushi exist with different virulence. Delayed diagnosis can result in complication and significant morbidity and mortality. Here, we report three cases of neonatal hepatitis with acute liver failure caused by scrub typhus to increase awareness.
Parvovirus B19 Infection in a Fatal Case of Acute Liver Failure.

Science.gov (United States)

Leon, Luciane Almeida Amado; Alves, Arthur Daniel Rocha; Garcia, Rita de Cássia Nasser Cubel; Melgaço, Juliana Gil; de Paula, Vanessa Salete; Pinto, Marcelo Alves

2017-12-01

B19V has been proposed as an etiologic agent for hepatitis, mainly in children, but this is a rare clinical occurrence. In this article, we report a case of non-A-E acute liver failure in an immunocompetent child with B19 infection. The clinical findings of severe anemia and pancytopenia combined with the detection of anti-B19 Immunoglobulin G (IgG), B19 DNA and B19 mRNA in liver indicate a persistent infection and suggest a diagnosis of parvovirus B19-associated acute liver failure.
Acute-on-chronic liver failure: a review

Directory of Open Access Journals (Sweden)

Zamora Nava LE

2014-04-01

Full Text Available Luis Eduardo Zamora Nava,1 Jonathan Aguirre Valadez,2 Norberto C Chávez-Tapia,3 Aldo Torre21Department of Endoscopy, 2Department of Gastroenterology, National Institute of Medical Sciences and Nutrition Salvador Zubirán, 3Obesity and Digestive Diseases Unit, Medica Sur Clinic and Foundation, Mexico City, MexicoAbstract: There is no universally accepted definition of acute-on-chronic liver failure; however, it is recognized as an entity characterized by decompensation from an underlying chronic liver disease associated with organ failure that conveys high short-term mortality, with alcoholism and infection being the most frequent precipitating events. The pathophysiology involves inflammatory processes associated with a trigger factor in susceptible individuals (related to altered immunity in the cirrhotic population. This review addresses the different definitions developed by leading research groups, epidemiological and pathophysiological aspects, and the latest treatments for this entity.Keywords: acute-on-chronic liver failure, cirrhosis, organ failure, acute kidney injury, infection
Acute liver failure in Cuban children.

Science.gov (United States)

Silverio, César E; Smithen-Romany, Chleo Y; Hondal, Norma I; Díaz, Hetzel O; Castellanos, Marlen I; Sosa, Oramis

2015-01-01

Acute liver failure is rare in pediatric patients and is one of the most challenging medical emergencies due to its prognostic and therapeutic implications. The best scientific evidence worldwide comes from multicenter studies in developed countries. In Cuba, there are no prior studies of this disorder in children. Describe the main clinical features of Cuban children treated at a national referral center for acute liver failure, as defined by recognized diagnostic criteria for pediatric patients. A case series study was conducted comprising patients diagnosed with acute liver failure treated from 2005 to 2011 in the hepatology and liver transplant service at Havana's William Soler University Children's Hospital. Variables were age group, etiology of acute liver failure, grade of hepatic encephalopathy, blood chemistry variables, and clinical outcome (whether or not spontaneous recovery of liver function occurred). Associations between variables were assessed using contingency tables, and case fatality was calculated, as well as relative risk with its 95% confidence interval. The Mann-Whitney U test was used to compare means of laboratory test results. Median age of the 31 patients studied (14 boys and 17 girls) was 24 months (range 1-180). Time between symptom onset and diagnosis of acute liver failure was 25.1 days (SD 16.8). Infection was the most common etiology, present in 61.3% of cases (19/31); nonhepatotropic viruses, especially cytomegalovirus, predominated in infants. Spontaneous recovery occurred in 15 patients (48.4%), 3 (9.7%) received transplants, and 13 died, for a case fatality of 41.9%. Outcome was not associated with etiology (p = 0.106), but was statistically associated with degree of hepatic encephalopathy (p failure in Cuban children calls for further epidemiologic study and identification of local underlying determinants of this phenomenon.
Potentially damaging failure modes of high- and medium-voltage electrical equipment

International Nuclear Information System (INIS)

Hoy, H.C.

1984-01-01

The high- and medium-voltage electrical equipment failures of both nuclear and nonnuclear electric utilities have been reviewed for possible disruptive failure modes that would be of special concern in a nuclear power plant. The resulting emphasis was on the electrical faults of transformers, switchgear (circuit breakers), lightning (surge) arrestors, high-voltage cabling and buswork, control boards, and other electrical equipment that, through failure, can be the initiating event that may expand the original fault to nearby or associated equipment. Many failures of such equipment were found and documented, although the failure rate of electrical equipment in utilities is historically quite low. Nuclear plants record too few failures to be statistically valid, but failures that have been recorded show that good design usually restricts the failure to a single piece of equipment. Conclusions and recommendations pertaining to the design, maintenance, and operation of the affected electrical equipment are presented
New treatment of low probability events with particular application to nuclear power plant incidents

Energy Technology Data Exchange (ETDEWEB)

Critchley, O.H.

1986-01-01

The 'New Treatment' attempts to resolve the 'Zero-Infinity Dilemmas' posed by the threat of low probability events (LPE) philosophical approach which rejects mathematical idealism in favour of the engineering pragmatism that is characteristic of the scientific method. The LPE is seen as a rare singularity in the stream of 'Event-noise' of mundane, untoward incidents that afflict industrial systems. Engineering inspection which has evolved as a regulatory mechanism can be effective in reducing this 'noise' and the competent inspector is able to recognise the 'loss of resistance to failure' which so often comes before an LPE. Despite that an intractable residual risk remains, but this can be made societally tolerable if there is a justifiable conviction that safety is defended by trustworthy engineering. In an age marked by an increasing complexity and sophistication in its science and technology, the engineer is emerging as the proper central decision maker in such matters standing, athwart pure administration and theory on the one hand and expertise and practice on the other. Moreover, evidence that his intellect may be peculiarly adapted for such a role is coming from recent findings in neuropsychology. The Nuclear Installations Inspectorate is cited as an exemplar of the engineering inspection needed to apprehend those human fallibilities in design and application to which most catastrophic failures of technology are due. However, such regulatory systems and the assessment functions associated with them lack accountability and, as an interpretation of Goedel's theorem suggests, cannot assess their own efficiency. Independent, disinterested appraisal assisted by Signal Detection Theory is offered as a remedy.
Lemierre's Syndrome - A rare cause of disseminated sepsis requiring multi-organ support.

Science.gov (United States)

Rae, John; Misselbrook, Katie

2017-11-01

Lemierre's syndrome is a rare complication of acute pharyngitis characterised by septicaemia with infective thrombophlebitis of the internal jugular vein, most commonly due to Fusobacterium necrophorum . It characteristically affects healthy young adults causing persistent pyrexia and systemic sepsis presenting several days after an initial pharyngitis. Septic emboli seed via the bloodstream to distant sites including the lung, joints, skin, liver, spleen and brain. Prolonged antimicrobial therapy is required and admission to intensive care common. This once rare condition is increasing in incidence but awareness amongst clinicians is low. We present a classic case in a young man who developed multi-organ failure requiring intensive care support and describe the epidemiology, pathophysiology, microbiology, clinical features and management of the disease.
In-hospital management and outcomes of acute coronary syndromes in relation to prior history of heart failure.

Science.gov (United States)

Zhang, Hanfei; Goodman, Shaun G; Yan, Raymond T; Steg, Ph Gabriel; Kornder, Jan M; Gyenes, Gabor T; Grondin, Francois R; Brieger, David; DeYoung, J Paul; Gallo, Richard; Yan, Andrew T

2016-06-01

The prognostic significance of prior heart failure in acute coronary syndromes has not been well studied. Accordingly, we evaluated the baseline characteristics, management patterns and clinical outcomes in patients with acute coronary syndromes who had prior heart failure. The study population consisted of acute coronary syndrome patients in the Global Registry of Acute Coronary Events, expanded Global Registry of Acute Coronary Events and Canadian Registry of Acute Coronary Events between 1999 and 2008. Of the 13,937 eligible patients (mean age 66±13 years, 33% female and 28.3% with ST-elevation myocardial infarction), 1498 (10.7%) patients had a history of heart failure. Those with prior heart failure tended to be older, female and had lower systolic blood pressure, higher Killip class and creatinine on presentation. Prior heart failure was also associated with significantly worse left ventricular systolic function and lower rates of cardiac catheterization and coronary revascularization. The group with previous heart failure had significantly higher rates of acute decompensated heart failure, cardiogenic shock, myocardial (re)infarction and mortality in hospital. In multivariable analysis, prior heart failure remained an independent predictor of in-hospital mortality (odds ratio 1.48, 95% confidence interval 1.08-2.03, p=0.015). Prior heart failure was associated with high risk features on presentation and adverse outcomes including higher adjusted in-hospital mortality in acute coronary syndrome patients. However, acute coronary syndrome patients with prior heart failure were less likely to receive evidence-based therapies, suggesting potential opportunities to target more intensive treatment to improve their outcome. © The European Society of Cardiology 2015.
Burden of rare variants in ALS genes influences survival in familial and sporadic ALS.

Science.gov (United States)

Pang, Shirley Yin-Yu; Hsu, Jacob Shujui; Teo, Kay-Cheong; Li, Yan; Kung, Michelle H W; Cheah, Kathryn S E; Chan, Danny; Cheung, Kenneth M C; Li, Miaoxin; Sham, Pak-Chung; Ho, Shu-Leong

2017-10-01

Genetic variants are implicated in the development of amyotrophic lateral sclerosis (ALS), but it is unclear whether the burden of rare variants in ALS genes has an effect on survival. We performed whole genome sequencing on 8 familial ALS (FALS) patients with superoxide dismutase 1 (SOD1) mutation and whole exome sequencing on 46 sporadic ALS (SALS) patients living in Hong Kong and found that 67% had at least 1 rare variant in the exons of 40 ALS genes; 22% had 2 or more. Patients with 2 or more rare variants had lower probability of survival than patients with 0 or 1 variant (p = 0.001). After adjusting for other factors, each additional rare variant increased the risk of respiratory failure or death by 60% (p = 0.0098). The presence of the rare variant was associated with the risk of ALS (Odds ratio 1.91, 95% confidence interval 1.03-3.61, p = 0.03), and ALS patients had higher rare variant burden than controls (MB, p = 0.004). Our findings support an oligogenic basis with the burden of rare variants affecting the development and survival of ALS. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.
Health Professionals' Expectations Versus Experiences of Internet-Based Telemonitoring : Survey Among Heart Failure Clinics

NARCIS (Netherlands)

de Vries, Arjen E.; van der Wal, Martje H. L.; Nieuwenhuis, Maurice M. W.; de Jong, Richard M.; van Dijk, Rene B.; Jaarsma, Tiny; Hillege, Hans L.

Background: Although telemonitoring is increasingly used in heart failure care, data on expectations, experiences, and organizational implications concerning telemonitoring are rarely addressed, and the optimal profile of patients who can benefit from telemonitoring has yet to be defined. Objective:

Scintillating bolometers: A promising tool for rare decays search

Energy Technology Data Exchange (ETDEWEB)

Pattavina, L., E-mail: luca.pattavina@mib.infn.it

2013-12-21

The idea of using a scintillating bolometer was first suggested for solar neutrino experiments in 1989. After many years of developments, now we are able to exploit this experimental technique, based on the calorimetric approach with cryogenic particle detectors, to investigate rare events such as Neutrinoless Double Beta Decay and interaction of Dark Matter candidates. The possibility to have high resolution detectors in which a very large part of the natural background can be discriminated with respect to the weak expected signal is very appealing. The goal to distinguish the different types of interactions in the detector can be achieved by means of scintillating bolometer. The simultaneous read-out of the heat and scintillation signals made with two independent bolometers enable this precious feature leading to possible background free experiment. In the frame of the LUCIFER project we report on how exploiting this technique to investigate Double Beta Decay for different isotope candidates. Moreover we demonstrate how scintillating bolometers are suited for investigating other rare events such as α decays of long living isotopes of lead and bismuth.
The Frasnian-Famennian mass killing event(s), methods of identification and evaluation

Science.gov (United States)

Geldsetzer, H. H. J.

1988-01-01

The absence of an abnormally high number of earlier Devonian taxa from Famennian sediments was repeatedly documented and can hardly be questioned. Primary recognition of the event(s) was based on paleontological data, especially common macrofossils. Most paleontologists place the disappearance of these common forms at the gigas/triangularis contact and this boundary was recently proposed as the Frasnian-Famennian (F-F) boundary. Not unexpectedly, alternate F-F positions were suggested caused by temporary Frasnian survivors or sudden post-event radiations of new forms. Secondary supporting evidence for mass killing event(s) is supplied by trace element and stable isotope geochemistry but not with the same success as for the K/T boundary, probably due to additional 300 ma of tectonic and diagenetic overprinting. Another tool is microfacies analysis which is surprisingly rarely used even though it can explain geochemical anomalies or paleontological overlap not detectable by conventional macrofacies analysis. The combination of microfacies analysis and geochemistry was applied at two F-F sections in western Canada and showed how interdependent the two methods are. Additional F-F sections from western Canada, western United States, France, Germany and Australia were sampled or re-sampled and await geochemical/microfacies evaluation.
Rare earth metals, rare earth hydrides, and rare earth oxides as thin films

International Nuclear Information System (INIS)

Gasgnier, M.

1980-01-01

The review deals with pure rare earth materials such as rare earth metals, rare earth hydrides, and rare earth oxides as thin films. Several preparation techniques, control methods, and nature of possible contaminations of thin films are described. These films can now be produced in an extremely well-known state concerning chemical composition, structure and texture. Structural, electric, magnetic, and optical properties of thin films are studied and discussed in comparison with the bulk state. The greatest contamination of metallic rare earth thin films is caused by reaction with hydrogen or with water vapour. The compound with an f.c.c. structure is the dihydride LnH 2 (Ln = lanthanides). The oxygen contamination takes place after annealing at higher temperatures. Then there appears a compound with a b.c.c. structure which is the C-type sesquioxide C-Ln 2 O 3 . At room atmosphere dihydride light rare earth thin films are converted to hydroxide Ln(OH) 3 . For heavy rare earth thin films the oxinitride LnNsub(x)Osub(y) is observed. The LnO-type compound was never seen. The present review tries to set the stage anew for the investigations to be undertaken in the future especially through the new generations of electron microscopes
Rationale and design of the Aquapheresis Versus Intravenous Diuretics and Hospitalization for Heart Failure (AVOID-HF) trial.

Science.gov (United States)

Costanzo, Maria Rosa; Negoianu, Daniel; Fonarow, Gregg C; Jaski, Brian E; Bart, Bradley A; Heywood, J Thomas; Nabut, Jose L; Schollmeyer, Michael P

2015-09-01

In patients hospitalized with acutely decompensated heart failure, unresolved signs and symptoms of fluid overload have been consistently associated with poor outcomes. Regardless of dosing and type of administration, intravenous loop diuretics have not reduced heart failure events or mortality in patients with acutely decompensated heart failure. The results of trials comparing intravenous loop diuretics to mechanical fluid removal by isolated venovenous ultrafiltration have yielded conflicting results. Studies evaluating early decongestive strategies have shown that ultrafiltration removed more fluid and was associated with fewer heart failure-related rehospitalization than intravenous loop diuretics. In contrast, when used in the setting of worsening renal function, ultrafiltration was associated with poorer renal outcomes and no reduction in heart failure events. The AVOID-HF trial seeks to determine if an early strategy of ultrafiltration in patients with acutely decompensated heart failure is associated with fewer heart failure events at 90 days compared with a strategy based on intravenous loop diuretics. Study subjects from 40 highly experienced institutions are randomized to either early ultrafiltration or intravenous loop diuretics. In both treatment arms, fluid removal therapies are adjusted according to the patients' hemodynamic condition and renal function. The study was unilaterally terminated by the sponsor in the absence of futility and safety concerns after the enrollment of 221 subjects, or 27% of the originally planned sample size of 810 patients. The AVOID-HF trial's principal aim is to compare the safety and efficacy of ultrafiltration vs that of intravenous loop diuretics in patients hospitalized with acutely decompensated heart failure. Because stepped treatment approaches are applied in both ultrafiltration and intravenous loop diuretics groups and the primary end point is time to first heart failure event within 90 days, it is hoped that
Common cause failure rate estimates for diesel generators in nuclear power plants

International Nuclear Information System (INIS)

Steverson, J.A.; Atwood, C.L.

1982-01-01

Common cause fault rates for diesel generators in nuclear power plants are estimated, using Licensee Event Reports for the years 1976 through 1978. The binomial failure rate method, used for obtaining the estimates, is briefly explained. Issues discussed include correct classification of common cause events, grouping of the events into homogeneous data subsets, and dealing with plant-to-plant variation
Using variable transformations to perform common event analysis

International Nuclear Information System (INIS)

Worrell, R.B.

1977-01-01

Any analytical method for studying the effect of common events on the behavior of a system is considered as being a form of common event analysis. The particular common events that are involved often represent quite different phenomena, and this has led to the development of different kinds of common event analysis. For example, common mode failure analysis, common cause analysis, critical location analysis, etc., are all different kinds of common event analysis for which the common events involved represent different phenomena. However, the problem that must be solved for each of these different kinds of common event analysis is essentially the same: Determine the effect of common events on the behavior of a system. Thus, a technique that is useful in achieving one kind of common event analysis is often useful in achieving other kinds of common event analysis
Procedures for treating common cause failures in safety and reliability studies: Analytical background and techniques

International Nuclear Information System (INIS)

Mosleh, A.; Fleming, K.N.; Parry, G.W.; Paula, H.M.; Worledge, D.H.; Rasmuson, D.M.

1989-01-01

Volume I of this report presents a framework for the inclusion of the impact of common cause failures in risk and reliability evaluations. Common cause failures are defined as that subset of dependent failures for which causes are not explicitly included in the logic model as basic events. The emphasis here is on providing procedures for a practical, systematic approach that can be used to perform and clearly document the analysis. The framework and the methods discussed for performing the different stages of the analysis integrate insights obtained from engineering assessments of the system and the historical evidence from multiple failure events into a systematic, reproducible, and defensible analysis. This document, Volume 2, contains a series of appendices that provide additional background and methodological detail on several important topics discussed in Volume I
Maxillary Osteomyelitis: A Rare Entity

Directory of Open Access Journals (Sweden)

Ayaaz Habib

2016-01-01

Full Text Available Osteomyelitis of the maxilla is now a rare event with the advent of antibiotics. The two predominant causes are odontogenic infections and sinusitis. Immunocompromised states such as diabetes, HIV, and malnutrition increase the risk of osteomyelitis. It is important to recognize this early as it is a difficult entity to treat with potentially serious consequences. We report an unusual case of right sided maxillary osteomyelitis in a lady with poorly controlled diabetes in rural Lincolnshire. Biopsy of the right maxillary bone showed features of acute osteomyelitis. This responded well to a prolonged course of oral antibiotics.
Dam failure analysis for the Lago de Matrullas Dam, Orocovis, Puerto Rico

Science.gov (United States)

Torres-Sierra, Heriberto; Gómez-Fragoso, Julieta

2015-01-01

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed a hydrologic and hydraulic study to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago de Matrullas Dam, located within the headwaters of the Río Grande de Manatí. The hydrologic study yielded outflow hydrographs and peak discharges for Lago de Matrullas and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation (PMP) event, (2) a 24-hour PMP event, and (3) a 100-year-recurrence, 24-hour rainfall event. The hydraulic study simulated the hypothetical dam failure of Lago de Matrullas using hypothetical flood hydrographs generated from the hydrologic study and selected dam breach parameters. The flood wave resulting from the failure was downstream-routed through the lower reaches of the Río Matrullas, the Río Toro Negro, and the Río Grande de Manatí for determination of water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” (no precipitation) conditions. The Hydrologic Modeling System (HEC–HMS) and the River Analysis System (HEC–RAS) computer programs, developed by the Hydrologic Engineering Center (HEC) of the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was performed using the unsteady-state flow module available in the HEC–RAS model.
Reducing the incidence of adverse events in anesthesia practice

OpenAIRE

BELAVIĆ, MATIJA; LONČARIĆ-KATUŠIN, MIRJANA; ŽUNIĆ, JOSIP

2013-01-01

Background and purpose: adverse event during anesthesia is defined as an event that may result in the development of complications and is caused by human error, failure of the apparatus, the selected anesthetic techniques and individual reaction of the patient. Timely detection of adverse events prevents complications and their analysis through the register of the same to the adoption of preventive and remedial measures. Materials and methods:The Department of Anesthesiology in General...
Cardiac arrest following ventilator fire: A rare cause

Directory of Open Access Journals (Sweden)

K Nazeer Ahmed

2012-01-01

Full Text Available Operating room fires are rare events, but when occur they result in serious and sometimes fatal consequences. Anaesthesia ventilator fire leading to cardiac arrest is a rare incident and has not been reported. We report a near catastrophic ventilator fire leading to cardiac arrest in a patient undergoing subtotal thyroidectomy. In the present case sparks due to friction or electrical short circuit within the ventilator might have acted as source of ignition leading to fire and explosion in the oxygen rich environment. The patient was successfully resuscitated and revived with uneventful recovery and no adverse sequelae. The cardiac arrest was possibly due to severe hypoxia resulting from inhalation of smoke containing high concentrations of carbon monoxide and other noxious gases.
OPDE-The international pipe failure data exchange project

Energy Technology Data Exchange (ETDEWEB)

Lydell, Bengt [OPDE Clearinghouse, 16917 S. Orchid Flower Trail, Vail, AZ 85641-2701 (United States)], E-mail: boylydell@msn.com; Riznic, Jovica [Canadian Nuclear Safety Commission, Operational Engineering Assessment Division, PO Box 1046, Station B, Ottawa, Ont. K1P 5S9 (Canada)], E-mail: jovica.riznic@cnsc-ccsn.gc.ca

2008-08-15

Certain member countries of the Organization for Economic Cooperation and development (OECD) in 2002 established the OECD pipe failure data exchange project (OPDE) to produce an international database on the piping service experience applicable to commercial nuclear power plants. OPDE is operated under the umbrella of the OECD Nuclear Energy Agency (NEA). The Project collects pipe failure data including service-induced wall thinning, part through-wall crack, pinhole leak, leak, and rupture/severance (i.e., events involving large through-wall flow rates up to and beyond the make-up capacity of engineered safeguards systems). The part through-wall events include degradation in excess of design code allowable for pipe wall thinning or crack depth. OPDE also addresses such degradation that could have generic implications regarding the reliability of in-service inspection. Currently the OPDE database includes approximately 3,700 records on pipe failure affecting ASME Code Class 1 through 3 and non-safety-related (non-Code) piping. This paper presents the motivations and objectives behind the establishment of the OPDE project. The paper also summarizes the unique data quality considerations that are associated with the reporting and recording of piping component degradation and failure. An overview of the database content is included to place it in perspective relative to past efforts to systematically collect and evaluate service experience data on piping performance. Finally, a brief summary is given of current database application studies.
OPDE-The international pipe failure data exchange project

International Nuclear Information System (INIS)

Lydell, Bengt; Riznic, Jovica

2008-01-01

Certain member countries of the Organization for Economic Cooperation and development (OECD) in 2002 established the OECD pipe failure data exchange project (OPDE) to produce an international database on the piping service experience applicable to commercial nuclear power plants. OPDE is operated under the umbrella of the OECD Nuclear Energy Agency (NEA). The Project collects pipe failure data including service-induced wall thinning, part through-wall crack, pinhole leak, leak, and rupture/severance (i.e., events involving large through-wall flow rates up to and beyond the make-up capacity of engineered safeguards systems). The part through-wall events include degradation in excess of design code allowable for pipe wall thinning or crack depth. OPDE also addresses such degradation that could have generic implications regarding the reliability of in-service inspection. Currently the OPDE database includes approximately 3,700 records on pipe failure affecting ASME Code Class 1 through 3 and non-safety-related (non-Code) piping. This paper presents the motivations and objectives behind the establishment of the OPDE project. The paper also summarizes the unique data quality considerations that are associated with the reporting and recording of piping component degradation and failure. An overview of the database content is included to place it in perspective relative to past efforts to systematically collect and evaluate service experience data on piping performance. Finally, a brief summary is given of current database application studies
Anthology of the Development of Radiation Transport Tools as Applied to Single Event Effects

Science.gov (United States)

Reed, R. A.; Weller, R. A.; Akkerman, A.; Barak, J.; Culpepper, W.; Duzellier, S.; Foster, C.; Gaillardin, M.; Hubert, G.; Jordan, T.; Jun, I.; Koontz, S.; Lei, F.; McNulty, P.; Mendenhall, M. H.; Murat, M.; Nieminen, P.; O'Neill, P.; Raine, M.; Reddell, B.; Saigné, F.; Santin, G.; Sihver, L.; Tang, H. H. K.; Truscott, P. R.; Wrobel, F.

2013-06-01

This anthology contains contributions from eleven different groups, each developing and/or applying Monte Carlo-based radiation transport tools to simulate a variety of effects that result from energy transferred to a semiconductor material by a single particle event. The topics span from basic mechanisms for single-particle induced failures to applied tasks like developing websites to predict on-orbit single event failure rates using Monte Carlo radiation transport tools.
Distributions of component failure rates, estimated from LER data

International Nuclear Information System (INIS)

Atwood, C.L.

1985-01-01

Past analyses of Licensee Event Report (LER) data have noted that component failure rates vary from plant to plant, and have estimated the distributions by two-parameter γ distributions. In this study, a more complicated distributional form is considered, a mixture of γs. This could arise if the plants' failure rates cluster into distinct groups. The method was applied to selected published LER data for diesel generators, pumps, valves, and instrumentation and control assemblies. The improved fits from using a mixture rather than a single γ distribution were minimal, and not statistically significant. There seem to be two possibilities: either explanatory variables affect the failure rates only in a gradual way, not a qualitative way; or, for estimating individual component failure rates, the published LER data have been analyzed to the limit of resolution
Rare combination of left-sided congenital diaphragmatic hernia and omphalocele.

Science.gov (United States)

Chee, Yuet Yee; Wong, Siu Chun Mabel; Wong, Ming Sum Rosanna

2017-08-07

We reported a rare case of left-sided posterolateral congenital diaphragmatic hernia (CDH) and omphalocele, which is not associated with chromosomal abnormalities or other syndromes. Omphalocele was detected antenatally (CDH was not detected in antenatal ultrasound). The patient suffered from respiratory failure secondary to severe pulmonary hypertension. As the combination of CDH and omphalocele is rare and with the abdominal content herniating into the omphalocele instead of the thorax, antenatal diagnosis of such condition can be difficult. Unlike other reported cases in the literature, our patient's respiratory condition has been improving with time and is surviving beyond the infancy period. We believe this to be the first such survival case reported in the literature. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
McKittrick-Wheelock syndrome - a rare cause of acute renal failure.

Science.gov (United States)

Popescu, Alina; Orban-Schiopu, Ana-Maria; Becheanu, Gabriel; Diculescu, Mircea

2005-03-01

Fluid and electrolyte hypersecretion in the villous adenoma of the rectum is presented in the case of a 74 year old man presenting with a severe fluid imbalance. The patient had a 2-year history of mucous diarrhea and, on admission, presented prerenal uremia, hyponatremia and severe hypokalemia. At sigmoidoscopy, a 6/4 cm villous adenoma of the rectum was found. The increased loss of volume, followed by exhaustion of the physiological compensation mechanisms, led to a life-threatening hypokalemia, as well as to acute renal failure. Conservative treatment was followed by a temporary improvement of the renal function. Alternative treatment was: endocavitary irradiation, endoscopic resection and radical tumor surgery. The surgical removal of the adenoma led to complete recovery of the symptoms. The McKittrick-Wheelock syndrome can be a problem of difficult diagnosis, both for the gastroenterologist and also for the nephrologist. The patient may develop severe complications, which require a sustained treatment.
Topology optimization of reduced rare-earth permanent magnet arrays with finite coercivity

Science.gov (United States)

Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Rowe, A.

2018-05-01

The supply chain risk of rare-earth permanent magnets has yielded research efforts to improve both materials and magnetic circuits. While a number of magnet optimization techniques exist, literature has not incorporated the permanent magnet failure process stemming from finite coercivity. To address this, a mixed-integer topology optimization is formulated to maximize the flux density of a segmented Halbach cylinder while avoiding permanent demagnetization. The numerical framework is used to assess the efficacy of low-cost (rare-earth-free ferrite C9), medium-cost (rare-earth-free MnBi), and higher-cost (Dy-free NdFeB) permanent magnet materials. Novel magnet designs are generated that produce flux densities 70% greater than the segmented Halbach array, albeit with increased magnet mass. Three optimization formulations are then explored using ferrite C9 that demonstrates the trade-off between manufacturability and design sophistication, generating flux densities in the range of 0.366-0.483 T.
Risk factors for oral methotrexate failure in patients with inflammatory polyarthritis: results from a UK prospective cohort study.

Science.gov (United States)

Bluett, James; Sergeant, Jamie C; MacGregor, Alex J; Chipping, Jacqueline R; Marshall, Tarnya; Symmons, Deborah P M; Verstappen, Suzanne M M

2018-03-20

Oral methotrexate (MTX) is the first-line therapy for patients with rheumatoid arthritis (RA). However, approximately one quarter of patients discontinue MTX within 12 months. MTX failure, defined as MTX cessation or the addition of another anti-rheumatic drug, is usually due adverse event(s) and/or inefficacy. The aims of this study were to evaluate the rate and predictors of oral MTX failure. Subjects were recruited from the Norfolk Arthritis Register (NOAR), a primary care-based inception cohort of patients with early inflammatory polyarthritis (IP). Subjects were eligible if they commenced MTX as their first DMARD and were recruited between 2000 and 2008. Patient-reported reasons for MTX failure were recorded and categorised as adverse event, inefficacy or other. The addition of a second DMARD during the study period was categorised as failure due to inefficacy. Cox proportional hazards regression models were used to assess potential predictors of MTX failure, accounting for competing risks. A total of 431 patients were eligible. The probability of patients remaining on MTX at 2 years was 82%. Competing risk analysis revealed that earlier MTX failure due to inefficacy was associated with rheumatoid factor (RF) positivity, younger age at symptom onset and higher baseline disease activity (DAS-28). MTX cessation due to an adverse event was less likely in the RF-positive cohort. RF-positive inflammatory polyarthritis patients who are younger with higher baseline disease activity have an increased risk of MTX failure due to inefficacy. Such patients may require combination therapy as a first-line treatment.
Core Competencies and the Prevention of School Failure and Early School Leaving

Science.gov (United States)

Bradshaw, Catherine P.; O'Brennan, Lindsey M.; McNeely, Clea A.

2008-01-01

There is an increasing awareness that school failure and early school leaving are processes, rather than discrete events, that often co-occur and can have lasting negative effects on children's development. Most of the literature has focused on risk factors for failure and dropout rather than on the promotion of competencies that can increase…

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