OBJECTIVES The purpose of this study was to analyse the correlation between preoperative systolic transvalvular flow patterns and proximal aortic wall lesions in patients undergoing surgery for bicuspid aortic valve (BAV) stenosis. METHODS A total of 48 consecutive patients with BAV stenosis (mean age 58 ± 9 years, 65% male) underwent aortic valve replacement (AVR) ± proximal aortic surgery f...

The immersed boundary method is an algorithm for simulating the interaction of immersed elastic bodies or boundaries with a viscous incompressible fluid. The immersed elastic material is represented in the fluid equations by a system or field of applied forces. The particular case of Stokes flow with applied forces on a periodic domain involves two related mathematical complications. One of the...

This paper investigates three scheduling algorithms and three inventory control policies to evaluate their effect on the system performance measures using computer simulation. The model chosen is a flow-shop type, computer assembly plant. Analysis is conducted on two scheduling measures (summation of process time and tardiness) and two inventory control measures (ordering cost and holding cost)...

Supply chain scheduling is a new emerging area of research. We study batch arrival scheduling problems at the manufacturer in a multi-level customer-centric supply chain, where promised job due dates are considered constraints which must be satisfied. We analyze the tradeoff between inventory holding costs and batch delivery costs. We show that the problems are closely related to batch scheduli...

Given an instance of the minimum cost flow problem, a version of the corresponding inverse problem, called the capacity inverse problem, is to modify the upper and lower bounds on arc flows as little as possible so that a given feasible flow x becomes optimal to the modified minimum cost flow problem. The modifications can be measured by different distances. Here, we consider the capacity inver...

Given an instance of the minimum cost flow problem, a version of the corresponding inverse problem, called the capacity inverse problem, is to modify the upper and lower bounds on arc flows as little as possible so that a given feasible flow x becomes optimal to the modified minimum cost flow problem. The modifications can be measured by different distances. Here, we consider the capacity inver...

A nowhere-zero 3-flow in a graph G is an assignment of a direction and a value of 1 or 2 to each edge of G such that, for each vertex v in G, the sum of the values of the edges with tail v equals the sum of the values of the edges with head v. Motivated by results about the region coloring of planar graphs, Tutte conjectured in 1966 that every 4-edge-connected graph has a nowhere-zero 3-flow. T...

Moses Rock dike is a Tertiary diatreme containing serpentinized ultramafic microbreccia (SUM) located on the Colorado Plateau in Utah. Field evidence indicates that SUM was emplaced first followed by breccias derived from the Permian strata exposed in the walls of the diatreme and finally by complex breccias containing basement and mantle-derived rocks. SUM is primarily found dispersed througho...

We study the I-ultrafilters on ω, where I is a a collection of subsets of a set X , usually R or ω1. The I-ultrafilters usually contain the P -points, often as a small proper subset. We study relations between I-ultrafilters for various I, and closure of I-ultrafilters under ultrafilter sums. We consider, but do not settle, the question whether I-ultrafilters always exist.