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Purpose The present study aims to demonstrate the performance assessment of flexible pavement structure in probabilistic framework with due consideration of spatial variability modeling of input parameter. Design/methodology/approach The analysis incorporates mechanistic–empirical approach in which numerical analysis with spatial variability modeling of input parameters, Monte Carlo simulations (MCS) and First Order Reliability Method (FORM) are combined together for the reliability analysis of the flexible pavement. Random field concept along with Cholesky decomposition technique is used for the spatial variability modeling of the input parameter and implemented in commercially available finite difference code FLAC for the numerical analysis of pavement structure. Findings Results of the reliability analysis, with spatial variability modeling of input parameter, are compared with the corresponding results obtained without considering spatial variability of parameters. Analyzing a particular three-layered flexible pavement structure, it is demonstrated that spatial variability modeling of input parameter provides more realistic treatment to property variations in space and influences the response of the pavement structure, as well as its performance assessment. Originality/value Research is based on reliability analysis approach, which can also be used in decision-making for quality control and flexible pavement design in a given environment of uncertainty and extent of spatially varying input parameters in a space.

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We report a rare case of benign thoracic dumb-bell tumor in the upper posterior mediastinum, which was successfully removed by posterolateral thoracotomy and foraminotomy, using intraoperative monitoring of spinal motor-evoked potentials. This technique has many advantages including minimal morbidity and mortality, a single incision, one-step complete resection with adequate exposure, spinal stabilization, avoidance of laminectomy, nerve root identification, and good predicted postoperative function.

Background The choice of a valve with an effective orifice area matching the body surface area and providing efficient hemodynamics is an important factor affecting mortality and morbidity in patients undergoing aortic valve replacement. Patients and methods Our preventative strategy was to implant a larger prosthetic valve by aortic root enlargement using the Nunez procedure in 17 patients between February 2010 and January 2011. The decision to enlarge the aortic root was taken when the 19-mm sizer could not be negotiated easily through the aortic root, or on the basis of body surface area of the patient or type of prosthesis available. Results Postoperative reductions in peak and mean pressure gradients across aortic valve of 12.8–16.5 and 10.2–12.6 mm Hg, respectively, were observed. Postoperative effective orifice areas of the aortic valves were 1.1–1.5 cm2. By upsizing the aortic valve, we were able to eliminate patient-prosthesis mismatch in 5 patients, and reduce severe patient-prosthesis mismatch to moderate in 11. Conclusion Aortic root enlargement is a safe procedure. Therefore, cardiac surgeons should not be reluctant to enlarge the aortic root with an autologous pericardial patch to permit implantation of an adequate size of aortic valve prosthesis, with minimal additional aortic crossclamp time and no added cost.