Geology topics

Azmy S. Ackleh

Publications and source records attributed to Azmy S. Ackleh.

3 recordsLinked to original sources

USGS2016

A model for the interaction of frog population dynamics with Batrachochytrium dendrobaties , Janthinobacterium lividium and temperature and its implication for chytridiomycosis management

Chytridiomycosis is an emerging disease caused by the fungal pathogen Batrachochytrium dendrobatidis ( Bd ) that poses a serious threat to frog populations worldwide. Several studies have shown that inoculation of bacterial species Janthinobacterium lividum ( Jl ) can mitigate the impact of the disease. However, there are many questions regarding this interaction. A mathematical model of a frog population infected with chytridiomycosis is developed to investigate how the inoculation of Jl could reduce the impact of Bd disease on frogs. The model also illustrates the important role of temperature in disease dynamics. The model simulation results suggest possible control strategies for Jl to limit the impact of Bd in various scenarios. However, a better knowledge of Jl life cycle is needed to fully understand the interaction of Jl , Bd , temperature and frogs.

Ecological Modelling↗

USGS2011

Fitting a structured juvenile-adult model for green tree frogs to population estimates from capture-mark-recapture field data

We derive point and interval estimates for an urban population of green tree frogs ( Hyla cinerea ) from capture–mark–recapture field data obtained during the years 2006–2009. We present an infinite-dimensional least-squares approach which compares a mathematical population model to the statistical population estimates obtained from the field data. The model is composed of nonlinear first-order hyperbolic equations describing the dynamics of the amphibian population where individuals are divided into juveniles (tadpoles) and adults (frogs). To solve the least-squares problem, an explicit finite difference approximation is developed. Convergence results for the computed parameters are presented. Parameter estimates for the vital rates of juveniles and adults are obtained, and standard deviations for these estimates are computed. Numerical results for the model sensitivity with respect to these parameters are given. Finally, the above-mentioned parameter estimates are used to illustrate the long-time behavior of the population under investigation.

Bulletin of Mathematical Biology↗

USGS2011

A case study of green tree frog population size estimation by repeated capture-mark-recapture method with individual tagging: A parametric bootstrap method vs. Jolly-Seber method

This paper deals with estimation of a green tree frog population in an urban setting using repeated capture–mark–recapture (CMR) method over several weeks with an individual tagging system which gives rise to a complicated generalization of the hypergeometric distribution. Based on the maximum likelihood estimation, a parametric bootstrap approach is adopted to obtain interval estimates of the weekly population size which is the main objective of our work. The method is computation-based; and programming intensive to implement the algorithm for re-sampling. This method can be applied to estimate the population size of any species based on repeated CMR method at multiple time points. Further, it has been pointed out that the well-known Jolly–Seber method, which is based on some strong assumptions, produces either unrealistic estimates, or may have situations where its assumptions are not valid for our observed data set.

Journal of Statistical Computation and Simulation↗