System Reliability Estimation in Multicomponent Exponential-Lindley Stress-Strength Models

A stress-strength model is formulated for a multi-component system consisting of k identical components. The k components of the system with random strengths ( ) 1 2 , ,..., k X X X are subjected to one of the r random stresses ( ) 1 2 , ,..., r Y Y Y . The estimation of system reliability based on maximum likelihood estimates (MLEs) and Bayes estimators in k component system are obtained when the system is either parallel or series with the assumption that strengths and stresses follow Lindley distribution and Exponential distribution respectively. A simulation study is conducted to compare MLE and Bayes estimator through the mean squared errors of the estimators

System reliability estimation in multicomponent exponential stress-strength models

A stress-strength model is formulated for a multi-component system consisting of k identical components. The k components of the system with random strengths (X1, X2, …, Xk) are subjected to one of the r random stresses (Xk+1, Xk+2, …, X k+r). The estimation of system reliability based on maximum likelihood estimates (MLEs) and Bayes estimators in k component system are obtained when the system is either parallel or series with the assumption that strengths and stresses follow exponential distribution. A simulation study is conducted to compare MLE and Bayes estimator through the mean squared errors of the estimator

System reliability estimation in multicomponent exponential stress-strength models

A stress-strength model is formulated for a multi-component system consisting of k identical components. The k components of the system with random strengths (X1, X2, …, Xk) are subjected to one of the r random stresses (Xk+1, Xk+2, …, X k+r). The estimation of system reliability based on maximum likelihood estimates (MLEs) and Bayes estimators in k component system are obtained when the system is either parallel or series with the assumption that strengths and stresses follow exponential distribution. A simulation study is conducted to compare MLE and Bayes estimator through the mean squared errors of the estimator

A novel medium size lactam ring analoges as antibacterial agents

A novel series of medium size (S)-3-alkyl-3,4,6,7-tetrahydro-1H-benzo[e][1,4]diazonine-2,5-dione (6a-f) analogues were synthesized from (E)-3-(2-nitrophenyl)acrylicacid (2) reacting with various amino acid esters using Di-isopropyl Carbodiimide as a coupling agent. The final cyclization is carried out by using reagent 1-Ethyl-3(3- dimethylaminopropyl) Carbodiimide Hydrochloride. The synthesized compounds have been supported by Mass, 1H-NMR and 13C-NMR. Further antibacterial studies were conducted, where some molecules are noticed with potent activity, especially molecule 6d shown highest activity which was also supported by molecular docking studies. All final molecules were docked with enzyme peptide deformylase to determine the probable binding conformation

Socioeconomic Deprivation and Survival After Heart Transplantation in England: An Analysis of the United Kingdom Transplant Registry.

BACKGROUND: Socioeconomic deprivation (SED) is associated with shorter survival across a range of cardiovascular and noncardiovascular diseases. The association of SED with survival after heart transplantation in England, where there is universal healthcare provision, is unknown. METHODS AND RESULTS: Long-term follow-up data were obtained for all patients in England who underwent heart transplantation between 1995 and 2014. We used the United Kingdom Index of Multiple Deprivation (UK IMD), a neighborhood level measure of SED, to estimate the relative degree of deprivation for each recipient. Cox proportional hazard models were used to examine the association between SED and overall survival and conditional survival (dependant on survival at 1 year after transplantation) during follow-up. Models were stratified by transplant center and adjusted for donor and recipient age and sex, ethnicity, serum creatinine, diabetes mellitus, and heart failure cause. A total of 2384 patients underwent heart transplantation. There were 1101 deaths during 17 040 patient-year follow-up. Median overall survival was 12.6 years, and conditional survival was 15.6 years. Comparing the most deprived with the least deprived quintile, adjusted hazard ratios for all-cause mortality were 1.27 (1.04-1.55; P=0.021) and 1.59 (1.22-2.09; P=0.001) in the overall and conditional models, respectively. Median overall survival and conditional survival were 3.4 years shorter in the most deprived quintile than in the least deprived. CONCLUSIONS: Higher SED is associated with shorter survival in heart transplant recipients in England and should be considered when comparing outcomes between centers. Future research should seek to identify modifiable mediators of this association.No direct funding was provided for the conduct of this study. JE completed part of this work as part of an academic clinical fellowship, where he spent time at the University of Cambridge, Cardiovascular Epidemiology Unit receiving training on research methods, supported by SK and EDA. The Cardiovascular Epidemiology Unit is funded by the UK Medical Research Council (G0800270), British Heart Foundation (SP/09/002), British Heart Foundation Cambridge Cardiovascular Centre of Excellence, and UK National Institute for Health Research Cambridge Biomedical Research Centre.This is the author accepted manuscript. The final version is available from American Heart Association via https://doi.org/10.1161/CIRCOUTCOMES.116.00265

Prognostic value of three iron deficiency definitions in patients with advanced heart failure

Aims: There is uncertainty about the definition of iron deficiency (ID) and the association between ID and prognosis in patients with advanced heart failure. We evaluated three definitions of ID in patients referred for heart transplantation. Methods and results: Consecutive patients assessed for heart transplantation at a single UK centre between January 2010 and May 2022 were included. ID was defined as (1) serum ferritin concentration of <100 ng/ml, or 100–299 ng/ml with transferrin saturation <20% (guideline definition), (2) serum iron concentration ≤13 μmol/L, or (3) transferrin saturation <20%. The primary outcome measure was a composite of all-cause mortality, urgent heart transplantation or need for mechanical circulatory support. Overall, 801 patients were included, and the prevalence of ID was 39–55% depending on the definition used. ID, defined by either serum iron or transferrin saturation, was an independent predictor of the primary outcome measure (hazard ratio [HR] 1.532, 95% confidence interval [CI] 1.264–1.944, and HR 1.595, 95% CI 1.323–2.033, respectively), but the same association was not seen with the guideline definition of ID (HR 1.085, 95% CI 0.8827–1.333). These findings were robust in multivariable Cox regression analysis. ID, by all definitions, was associated with lower 6-min walk distance, lower peak oxygen consumption, higher intra-cardiac filling pressures and lower cardiac output. Conclusions: Iron deficiency, when defined by serum iron concentration or transferrin saturation, was associated with increased frequency of adverse clinical outcomes in patients with advanced heart failure. The same association was not seen with guideline definition of ID

Visually estimated ejection fraction by two dimensional and triplane echocardiography is closely correlated with quantitative ejection fraction by real-time three dimensional echocardiography

<p>Abstract</p> <p>Background</p> <p>Visual assessment of left ventricular ejection fraction (LVEF) is often used in clinical routine despite general recommendations to use quantitative biplane Simpsons (BPS) measurements. Even thou quantitative methods are well validated and from many reasons preferable, the feasibility of visual assessment (eyeballing) is superior. There is to date only sparse data comparing visual EF assessment in comparison to quantitative methods available. The aim of this study was to compare visual EF assessment by two-dimensional echocardiography (2DE) and triplane echocardiography (TPE) using quantitative real-time three-dimensional echocardiography (RT3DE) as the reference method.</p> <p>Methods</p> <p>Thirty patients were enrolled in the study. Eyeballing EF was assessed using apical 4-and 2 chamber views and TP mode by two experienced readers blinded to all clinical data. The measurements were compared to quantitative RT3DE.</p> <p>Results</p> <p>There were an excellent correlation between eyeballing EF by 2D and TP vs 3DE (r = 0.91 and 0.95 respectively) without any significant bias (-0.5 ± 3.7% and -0.2 ± 2.9% respectively). Intraobserver variability was 3.8% for eyeballing 2DE, 3.2% for eyeballing TP and 2.3% for quantitative 3D-EF. Interobserver variability was 7.5% for eyeballing 2D and 8.4% for eyeballing TP.</p> <p>Conclusion</p> <p>Visual estimation of LVEF both using 2D and TP by an experienced reader correlates well with quantitative EF determined by RT3DE. There is an apparent trend towards a smaller variability using TP in comparison to 2D, this was however not statistically significant.</p

Analyse multidimensionnelle interactive de résultats de simulation (aide à la décision dans le domaine de l'agroécologie)

Dans cette thèse, nous nous sommes intéressés à l'analyse des données de simulation issues du modèle agro-hydrologique TNT. Les objectifs consistaient à élaborer des méthodes d'analyse des résultats de simulation qui replacent l'utilisateur au coeur du processus décisionnel, et qui permettent d'analyser et d'interpréter de gros volumes de données de manière efficace. La démarche développée consiste à utiliser des méthodes d'analyse multidimensionnelle interactive. Tout d'abord, nous avons proposé une méthode d'archivage des résultats de simulation dans une base de données décisionnelle (i.e. entrepôt de données), adaptée au caractère spatio-temporel des données de simulation produites. Ensuite, nous avons suggéré d'analyser ces données de simulations avec des méthodes d'analyse en ligne (OLAP) afin de fournir aux acteurs des informations stratégiques pour améliorer le processus d'aide à la prise de décision. Enfin, nous avons proposé deux méthodes d'extraction de skyline dans le contexte des entrepôts de données afin de permettre aux acteurs de formuler de nouvelles questions en combinant des critères environnementaux contradictoires, et de trouver les solutions compromis associées à leurs attentes, puis d'exploiter les préférences des acteurs pour détecter et faire ressortir les données susceptibles de les intéresser. La première méthode EC2Sky, permet un calcul incrémental et efficace des skyline en présence de préférences utilisateurs dynamiques, et ce malgré de gros volumes de données. La deuxième méthode HSky, étend la recherche des points skyline aux dimensions hiérarchiques. Elle permet aux utilisateurs de naviguer le long des axes des dimensions hiérarchiques (i.e. spécialisation / généralisation) tout en assurant un calcul en ligne des points skyline correspondants. Ces contributions ont été motivées et expérimentées par l'application de gestion des pratiques agricoles pour l'amélioration de la qualité des eaux des bassins versants agricoles, et nous avons proposé un couplage entre le modèle d'entrepôt de données agro-hydrologiques construit et les méthodes d'extraction de skyline proposées.This thesis concerns the analysis of simulation data generated by the agrohydrological model TNT. Our objective is to develop analytical methods for massive simulation results. We want to place the user at the heart of the decision-making process, while letting him handle and analyze large amounts of data in a very efficient way. Our first contribution is an original approach N-Catch, relying on interactive multidimensional analysis methods for archiving simulation results in a decisional database (i.e. data warehouse) adapted to the spatio-temporal nature of the simulation data. In addition, we suggest to analyze the simulation data with online analytical methods (OLAP) to provide strategic information for stakeholders to improve the decision making process. Our second contribution concern two methods for computing skyline queries in the context of data warehouses. These methods enable stakeholders to formulate new questions by combining conflicting environmental criteria, to find compromise solutions associated with their expectations, and to exploit the stakeholder preferences to identify and highlight the data of potential interest. The first method EC2Sky, focuses on how to answer efficiently and progressively skyline queries in the presence of several dynamic user preferences despite of large volume of data. The second method HSky, extends the skyline computation to hierarchical dimensions. It allows the user to navigate along the dimensions hierarchies (i.e. specialize / generalize) while ensuring the online computation of associated skylines. Finally, we present the application of our proposals for managing agricultural practices to improve water quality in agricultural watersheds. We propose a coupling between the agro-hydrological data warehouse model N-Catch and the proposed skyline computation methods.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF