The role of IL-6 for predicting neonatal sepsis: A systematic review and meta-analysis

Objective: Neonatal sepsis (NS) is a common and life-threatening disorder in infants. Previous studies showed that interleukin-6 (IL-6) may be a valid non-invasive and rapid method for diagnosis of NS. We conducted this review to assess the validity of IL-6 for predicting NS. Methods: This was a systematic review with meta-analysis. Embase, Medline and Web of Science databases were searched between January 1990 and December 2009. The search terms used were "cytokine", "neonate", "sepsis" and "interleukin-6". We used standard methods recommended for meta analyses of diagnostic test evaluations. The analysis was based on a summary ROC (SROC) curve. Meta-regression analysis was used to assess the effects of some confounding factors on the results of meta-analysis. Potential presence of publication bias was tested using funnel plots and the Egger test. Findings: Meta-analysis was performed on 13 publications including 353 infants with sepsis and 691 control infants. The pooled sensitivity and specificity of IL-6 was 0.79 and 0.84, respectively. The maximum joint sensitivity and specificity (i.e., the Q value) in SROC curve was 0.82 and the area under curve (AUC) was 0.89 (95% CI: 0.84-0.94). Meta-regression analysis showed that the diagnostic accuracy of IL-6 was not affected by confounding variables. The evaluation of publication bias showed that the Egger test was not significant (P=0.07). Conclusion: IL-6 seems to be a valid marker for predicting NS. It may be considered for early diagnosis of sepsis in neonatal care units. © 2011 by Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, All rights reserved

A Sequential Monte Carlo Approach for Online Stock Market Prediction Using Hidden Markov Models

A sequential Monte Carlo (SMC) algorithm prediction approach is developed based on joint probability distribution in hidden Markov Models (HMM). SMC methods, a general class of Monte Carlo methods, are typically used for sampling from sequences of distributions and simple examples of these algorithms are found extensively throughout the tracking and signal processing literature. Recent developments indicate that these techniques have much more general applicability and can be applied very effectively to statistical inference problems. Due to the problem involved in estimating the parameter of HMM, the HMM is represented in a state space model and the sequential Monte Carlo (SMC) method is used. Predictions are made using the SMC method in HMM and the corresponding on-line algorithm is developed. Daily stock price data from the banking sector of the Nigerian Stock Exchange (NSE) (price index between the years 1 January 2005 to 31 December 2008) are analyzed; experimental results reveal that the method proposed is effective

Performance-based Optimal Design of Cantilever Retaining Walls

Modern buildings should provide some degree of safety against severe earthquakes. However, it is not economically feasible to construct buildings that withstand extreme loads without avoiding damage. In performance-based design, structural engineers and owners work together to achieve the best possible balance between construction cost and seismic performance. In this study, by employing a metaheuristic optimization, we have tried to extend the concept of performance-based design to retaining wall structures. According to the AASHTO LRFD Bridge Design Specifications, permanent displacement of retaining structures are tolerable, as long as the movement does not lead to unacceptable damage to the structure or facilities located in or near the moving earth. The decision on performance expectations needs to be made by owners with structural engineers providing a realistic assessment of the cost of designing to avoid the movement. To make this assessment possible, we developed a multi-objective optimization framework for simultaneous minimization of the construction cost and the permanent displacement of cantilever retaining walls. The effectiveness of the proposed framework was evaluated in the design of a typical cantilever retaining wall of 8 meters in height, once with both a toe and heel slab and once with either of them. The results indicated that obtaining the Pareto front of optimal solutions for these objectives, provides useful information that helps owners to select a solution that is the most economical in a trade-off between the construction cost and performance expectation