Stability in a population model without random deaths by the Verhulst factor

✦ Synopsis

A large amount of population models use the concept of a carrying capacity. Simulated populations are bounded by invoking finite resources through a survival probability, commonly referred to as the Verhulst factor. The fact, however, that resources are not easily accounted for in actual biological systems makes the carrying capacity parameter ill-defined. Henceforth, we deem it essential to consider cases for which the parameter is unnecessary. This work demonstrates the possibility of Verhulst-free steady states using the Penna aging model, with one semelparous birth per adult. Stable populations are obtained by setting a mutation threshold that is higher than the reproduction age.

Renal insufficiency and anemia are indep

Renal insufficiency and anemia are independent risk factors for death among patients with acute myocardial infarction1,21As published material, the contents of this manuscript may not be cited, quoted, reproduced or published without the consent of the authors.2The analyses upon which this publication is based were performed under Contract Number 500-96-P704, entitled âOperation Utilization and Quality Control Peer Review Organization (PRO) for the State of Georgiaâ and sponsored by the Centers for Medicare and Medicaid Services (CMS), Department of Health and Human Services. The conclusions and opinions expressed, and methods used herein are those of the authors. They do not necessarily reflect CMS policy. The authors assume full responsibility for the accuracy and completeness of the ideas presented. This article is a direct result of the Health Care Quality Improvement Program initiated by CMS, which has encouraged identification of quality improvement projects derived from analysis of patterns of care, and therefore required no special funding on the part of this Contractor. Ideas and contributions to the authors concerning experience in engaging with issues presented are welcomed.

✍ Langston, Robert D.; Presley, Rodney; Flanders, W. Dana; Mcclellan, William M. 📂 Article 📅 2003 🏛 Nature Publishing Group 🌐 English ⚖ 373 KB