2 research outputs found
Employing Gaussian process priors for studying spatial variation in the parameters of a cardiac action potential model
Cardiac cells exhibit variability in the shape and duration of their action
potentials in space within a single individual. To create a mathematical model
of cardiac action potentials (AP) which captures this spatial variability and
also allows for rigorous uncertainty quantification regarding within-tissue
spatial correlation structure, we developed a novel hierarchical Bayesian model
making use of a latent Gaussian process prior on the parameters of a simplified
cardiac AP model which is used to map forcing behavior to observed voltage
signals. This model allows for prediction of cardiac electrophysiological
dynamics at new points in space and also allows for reconstruction of surface
electrical dynamics with a relatively small number of spatial observation
points. Furthermore, we make use of Markov chain Monte Carlo methods via the
Stan modeling framework for parameter estimation. We employ a synthetic data
case study oriented around the reconstruction of a sparsely-observed spatial
parameter surface to highlight how this approach can be used for spatial or
spatiotemporal analyses of cardiac electrophysiology
Fluid hunter motivation in Central Africa: Effects on behaviour, bushmeat and income
Individual motivation for the rural use of commonâpool resources (CPRs) can be fluid, with the line between subsistence and commercial often unclear and in flux. Implications of fluid motivation are understudied yet important for socialâecological systems (SESs), such as bushmeat hunting throughout Central Africa that is essential to local protein/nutrition, income and culture. Making locally informative predictions of multiple SESs nested within a landscapeâscale SES has been historically difficult, but communityâdriven participatory approaches provide new kinds and quantities of data, opening previously inaccessible doors for research and governance. We apply hierarchical Bayesian structural equation modelling to a novel dataset of 910 hunts from 111 gun and trap hunters across nine villages in Gabon, generated in a participatory process whereby hunters conducted GPS selfâfollows in conjunction with paraecologist surveys of their motivation, behaviour and offtake. We (i) establish the human behaviour driving gunâhunting and trapping success and predict its effect on offtake across villages and (ii) link fluid motivation of gun hunters to their behaviour, number of animals hunted, biomass yielded and income earned. Gun hunts across villages yielded more animals during the night than the day, and when hunters brought high amounts of ammunition and walked far distances from villages. Gun hunts were less successful when coupled with trapping while perâhunt success of trapping itself was generally low and difficult to predict. Fluid gun hunters hunted fewer animals when motivated strictly by subsistence, despite no reduction in ammunition brought or distance walked, while offtake from strictly commercial versus mixed motivation was the same. Numbers of animals hunted, biomass and income were tightly linked. We discuss the implications of these results for the ecological sustainability of hunting and participatory forecasting in bushmeat research and policy. Read the free Plain Language Summary for this article on the Journal blog