Matrix and agent-based modeling of threats to a diamond-backed terrapin population.

Population models are important tools for evaluating human impacts and potential management approaches on declining species. However, often studies are limited by constraints of the specific modeling approach. In this study we considered the persistence of a diamond-backed terrapin (Malaclemys terrapin) population using two distinct modeling approaches.

Applications of percolation theory to fungal spread with synergy.

There is increasing interest in the use of the percolation paradigm to analyse and predict the progress of disease spreading in spatially structured populations of animals and plants. The wider utility of the approach has been limited, however, by several restrictive assumptions, foremost of which is a strict requirement for simple nearest-neighbour transmission, in which the disease history of an individual is influenced only by that of its neighbours. In a recent paper, the percolation paradigm has been generalized to incorporate synergistic interactions in host infectivity and susceptibility, and the impact of these interactions on the invasive dynamics of an epidemic has been demonstrated.

Synergy in spreading processes: from exploitative to explorative foraging strategies.

An epidemiological model which incorporates synergistic effects that allow the infectivity and/or susceptibility of hosts to be dependent on the number of infected neighbors is proposed. Constructive synergy induces an exploitative behavior which results in a rapid invasion that infects a large number of hosts. Interfering synergy leads to a slower and sparser explorative foraging strategy that traverses larger distances by infecting fewer hosts.

Simulating the contact process in heterogeneous environments.

The one-dimensional contact process (CP) in a heterogeneous environment-a binary chain consisting of two types of site with different recovery rates-is investigated. It is argued that the commonly used random-sequential Monte Carlo simulation method which employs a discrete notion of time is not faithful to the rates of the contact process in a heterogeneous environment. Therefore, a modification of this algorithm along with two alternative continuous-time implementations are analyzed.

Extinction of epidemics in lattice models with quenched disorder.

The extinction of the contact process for epidemics in lattice models with quenched disorder is analyzed in the limit of small density of infected sites. It is shown that the problem in such a regime can be mapped to the quantum-mechanical one characterized by the Anderson Hamiltonian for an electron in a random lattice. It is demonstrated both analytically (self-consistent mean field) and numerically (by direct diagonalization of the Hamiltonian and by means of cellular automata simulations) that disorder enhances the contact process, given the mean values of random parameters are not influenced by disorder.

Medical malpractice and tort reform: a summary and look to the future.

In this article, the author describes the recent history and current status of tort reform in this country and provides an overview of various trends that are likely to shape the future of tort reform.

Good Samaritan laws: do state statutes protect your EMS staff?

Most state Good Samaritan laws are vague on the question of whether or not Good Samaritan immunities apply to emergencies that occur within a hospital or other medical facility. In general, such laws are broadly interpreted by state courts because their purpose is to encourage medical professionals to respond in emergencies. However, some state laws may need to be updated to meet the conditions of modern emergency medical care systems.

Hiring a CEO made (almost) easy.

Selecting a CEO and establishing his compensation and the terms of his employment are among the board's most important functions. This article suggests a series of steps intended to help the board approach the task in an organized and rational manner, from the development of a mission statement and job description through the recruitment of candidates to the development of a compensation package and personnel policies.

Helping the impaired physician.

Physician impairment is a growing problem, and the American Medical Association and several state medical associations are aggressively seeking solutions. In the hospital setting, the medical staff should recognize its responsibility for identifying sick physicians at the earliest possible time; the governing board in turn is responsible for seeing to it that the medical staff has a process in place for identifying and getting help for impaired physicians.

Prevalence of trachoma among Navajo Indian children.

Examination of some 6000 Navajo children in their schools in the Shiprock, New Mexico area between 1975 and 1977 yielded an overall prevalence of trachoma of 2.4%. The prevalence was highest for high schoolers (3.