An Integrated Simulation Environment for parallel and distributed system prototyping

The process of designing parallel and distributed computer systems requires predicting performance in response to given workloads. The scope and interaction of applications, operating systems, communication networks, processors, and other hardware and software lead to substantial system complexity. Development of virtual prototypes in lieu of physical prototypes can result in tremendous savings, especially when created in concert with a powerful model development tool. When high-fidelity models of parallel architecture are coupled with workloads generated from real parallel application code in an execution-driven simulation, the result is a potent design and analysis tool for parallel hardware and software alike. This paper introduces the concepts, mechanisms, and results of an Integrated Simulation Environment (ISE) that makes possible the rapid virtual prototyping and profiling of legacy and prototype parallel processing algorithms, architectures, and systems using a networked cluster of workstations. Performance results of virtual prototypes in ISE are shown to faithfully represent those of an equivalent hardware configuration, and the benefits of ISE for predicted performance comparisons are illustrated by a case study

Maintenance of the LDL Cholesterol:HDL Cholesterol Ratio in an Elderly Population Given a Dietary Cholesterol Challenge

We previously evaluated the responses to dietary cholesterol in children and young adults. In this study, the effects of dietary cholesterol on plasma lipids and LDL atherogenicity were evaluated in 42 elderly subjects (29 postmenopausal women and 13 men \u3e 60 y old). Our exclusion criteria were diabetes, heart disease, and the use of reductase inhibitors. The study followed a randomized crossover design in which subjects were assigned to consume the equivalent of 3 large eggs (EGG) daily or the same amount of a cholesterol-free, fat-free egg substitute (SUB) for a 1-mo period. After a 3-wk washout period, subjects were assigned to the alternate treatment. The concentration of plasma cholesterol after the EGG period varied among subjects. When all subjects were evaluated, there were significant increases in LDL cholesterol (LDL-C) (P \u3c 0.05) and HDL-C (P \u3c 0.001) for both men and women during the EGG period, resulting in no alterations in the LDL-C:HDL-C or the total cholesterol:HDL-C ratios. In addition, the LDL peak diameter was increased during the EGG period for all subjects. In contrast, the measured parameters of LDL oxidation, conjugated diene formation, and LDL lag time did not differ between the EGG and the SUB periods. We conclude from this study that dietary cholesterol provided by eggs does not increase the risk for heart disease in a healthy elderly population