János Karsai

Chlamydia trachomatis infection and the risk of perinatal mortality in Hungary

Abstract Introduction: Chlamydial infections of the genital tract are thought to often lead to preterm birth, which is the most important perinatal problem in Hungary. Aim of study: A multicenter study was carried out to determine the prevalence of Chlamydia trachomatis infection, risk factors for the infection and to relate the infection to perinatal mortality, accounting for potential confounding effects. Methods: The nucleic acid hybridization method (PACE2 Gen-Probe) was applied for the examination of Chlamydia trachomatis. Logistic regression analysis was used to assess risk. Results: A total of 6156 pregnant women were examined for the occurrence of Chlamydia trachomatis. The observed overall rate of chlamydial infection was 5.9%. Young age (less than 24 years old) (OR and 95% CI:1.6 (1.3–2.0)), unmarried status (1.5 (1.2–1.9)) and the high unemployment rate (2.1 (1.6–2.7)) were statistically significant predictors of the infection. In logistic regression analysis, chlamydial infection (1.9 (1.1–3.3)), high unemployment rate (1.5 (1.2–2.2)) and low birth weight (1.7 (1.1–2.7) were significant predictors of perinatal mortality. Conclusions: Testing pregnant women for diseases that can be transmitted perinatally is an important part of obstetric care. Screening for C. trachomatis of unmarried women under 24 years of age is suggested and need increased observation during labor.

Visualization and art in the mathematics classroom

In this paper we summarize our concepts and practice on computer-aided mathematical experimentation, and illustrate them byMathematica projects that we have developed for our research and the courses “Computer-aided mathematical modelling” and “Computer Algebra I–II” held for students of life sciences at University of Szeged and computational engineering at TFH Berlin, University of Applied Sciences.

On the Models of Metapopulations with Overcolonization

We consider ODE-meanfield as well as cellular automaton models of some two-species metapopulations (species fight for territory). The competing species can colonize not only empty patches but also overcolonize those which are occupied by the other. After a short summary of some single-species models, we investigate ODE models with overcolonization, in which no hierarchy is assumed between the competitors. We present results on the dynamics of the models. We give conditions for colonization and extinction strategies that either guarantee or exclude stability of the coexistence. We show that there can even appear unstable coexisting equilibrium. Then, we show experimental results (using Wolfram Mathematica) for stochastic cellular automata models of some aggressively spreading species, in particular some parasites, and compare our models with our field data concerning some Cuscuta species. Simulations give us a lot of information on special properties such as aggregation, diffusion, properties of the boundary of patches.