Using Cellular Automata to study the effect of competition for epidemic diseases

AbstractCellular Automata (CA) has shown to be a valuable approach in ecological modeling, in particular when dealing with local interactions between species and their environment. A stochastic cellular automata model, which included two competitors (the inferior species which is immune to a disease and the superior one which is sensitive to the disease), is constructed. Through time series analysis and spatial pattern analysis, the influence of competition effect upon the behavior of epidemic diseases has been investigated to know whether the competition effect is in favor of epidemics control. Then, some strategies for introducing competitors to the infectious system are explored. The result shows that introducing some right competitors into the infection region may be a considerable policy. The population with high colonization rate, low extinction rate and long colonization radius is introduced preferably. The result may give us some suggestions for epidemic control in conservation of wild populations

Stabilizing intransitive loops: self‐organized spatial structure and disjoint time frames in the coffee agroecosystem

It is familiar knowledge that population dynamics occur in both time and space. In this work, we incorporate three distinct but related theoretical schemata to qualitatively interrogate the complicated structure of part of a real agroecosystem. The three schemata are first, local dynamics translated into intransitive oscillators through spatial movement, second, stabilizing the system through spatial pattern, and third, formation of a self‐organized spatial pattern. The real system is the well‐studied autonomous pest control in the coffee agroecosystem, in which five insect species (one of which is a pest) are involved in creating a complex community structure that keeps the pest under control (the five species are an ant, Azteca sericeasur, a phorid fly parasitoid, Pseudacteon sp., a hymenopteran parasitoid, Coccophagus sp., a beetle predator, Azya orbigera, and the pest itself, the green coffee scale, Coccus viridis). We use the qualitative framing of the three theoretical schemata to develop a cellular automata model that casts the basic predator/prey (natural enemy/pest) system as an intransitive oscillator, and then explore the interaction of the two basic predator/prey systems as coupled oscillators within this model framework. We note that Gause’s principle of competitive exclusion is not violated with this basic framing (i.e., the two control agents cannot coexist theoretically), but that with a change in the spatial structure of the background habitat, coexistence can be maintained through the tradeoff between regional dispersal and local consumption. Finally, we explore how the other oscillator in the system (the ant and its phorid parasitoid) can act as a pilot system, creating the spatial structure in which the other two oscillators operate, but only in the context of disjoint time frames (between the two control agents and the pilot subsystem).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146945/1/ecs22489.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146945/2/ecs22489_am.pd

Red Queen Coevolution on Fitness Landscapes

Species do not merely evolve, they also coevolve with other organisms. Coevolution is a major force driving interacting species to continuously evolve ex- ploring their fitness landscapes. Coevolution involves the coupling of species fit- ness landscapes, linking species genetic changes with their inter-specific ecological interactions. Here we first introduce the Red Queen hypothesis of evolution com- menting on some theoretical aspects and empirical evidences. As an introduction to the fitness landscape concept, we review key issues on evolution on simple and rugged fitness landscapes. Then we present key modeling examples of coevolution on different fitness landscapes at different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.). Springer Series in Emergence, Complexity, and Computation, 201

Publisher Correction: Towards an ecosystem model of infectious disease

Correction to: Nature Ecology & Evolution https://doi.org/10.1038/s41559-021-01454-8, published online 17 May 2021

Towards an ecosystem model of infectious disease

Increasingly intimate associations between human society and the natural environment are driving the emergence of novel pathogens, with devastating consequences for humans and animals alike. Prior to emergence, these pathogens exist within complex ecological systems that are characterized by trophic interactions between parasites, their hosts and the environment. Predicting how disturbance to these ecological systems places people and animals at risk from emerging pathogens-and the best ways to manage this-remains a significant challenge. Predictive systems ecology models are powerful tools for the reconstruction of ecosystem function but have yet to be considered for modelling infectious disease. Part of this stems from a mistaken tendency to forget about the role that pathogens play in structuring the abundance and interactions of the free-living species favoured by systems ecologists. Here, we explore how developing and applying these more complete systems ecology models at a landscape scale would greatly enhance our understanding of the reciprocal interactions between parasites, pathogens and the environment, placing zoonoses in an ecological context, while identifying key variables and simplifying assumptions that underly pathogen host switching and animal-to-human spillover risk. As well as transforming our understanding of disease ecology, this would also allow us to better direct resources in preparation for future pandemics

From Linear to Additive Cellular Automata

This paper proves the decidability of several important properties of additive cellular automata over finite abelian groups. First of all, we prove that equicontinuity and sensitivity to initial conditions are decidable for a nontrivial subclass of additive cellular automata, namely, the linear cellular automata over \u207f, where is the ring \u2124/m\u2124. The proof of this last result has required to prove a general result on the powers of matrices over a commutative ring which is of interest in its own. Then, we extend the decidability result concerning sensitivity and equicontinuity to the whole class of additive cellular automata over a finite abelian group and for such a class we also prove the decidability of topological transitivity and all the properties (as, for instance, ergodicity) that are equivalent to it. Finally, a decidable characterization of injectivity and surjectivity for additive cellular automata over a finite abelian group is provided in terms of injectivity and surjectivity of an associated linear cellular automata over \u207f

Mathematische Biologie

[no abstract available

Progress in the producer-scrounger game : information use and spatial models

Les animaux grégaires en quête de ressources peuvent soit consacrer leurs efforts à la recherche (stratégie producteur) ou soit attendre que les producteurs réussissent à trouver ces ressources pour les y rejoindre (stratégie chapardeur). La profitabilité de chaque option peut être analysée par le jeu producteur-chapardeur. Ce jeu a été largement exploré aux plans théorique et empirique, mais plusieurs aspects demeurent toujours inexplorés. J'ai développé cinq modèles afin d'explorer l'approvisionnement social en lien avec l'utilisation d'information et les contraintes spatiales. Le premier modèle concerne l'évolution de règles d'apprentissage, des expressions mathématiques décrivant la valeur qu'un animal accorde aux options producteur et chapardeur en fonction des gains obtenus. J'ai démontré que la règle du relative pay-off sum est évolutivement stable et donc la meilleure disponible. Les paramètres de la règle attendue demeurent intrigants et demandent maintenant à être éplorés au niveau empirique. Le second modèle explorés plutôt l'effet de l'usage d'information sociale (chapardeur) chez un prédateur en examinant son effet sur l'évolution du niveau d'agrégation de ses proies. Le modèle démontre que les proies évoluent à différents niveaux d'agrégation en réponse à l'usage d'information sociale par leurs prédateurs et que cette relation affecte à la fois l'efficacité de recherche du prédateur et la survie des proies. Le troisième modèle teste l'hypothèse, générée à partir de recherche empirique sur les oies cendrées, selon laquelle la variation du niveau de hardiesse serait associée à un dimorphisme de producteurs hardis et de chapardeurs poltrons (bold et shy, respectivement) dans le jeu producteur-chapardeur. Le modèle réfute l'existence d'un tel dimorphisme, mais démontre néanmoins un effet environnemental fort des paramètres de l'approvisionnement social sur le niveau de hardiesse d'une population. Ce résultat a d'importantes implications pour le rôle de l'utilisation d'information et les effets spatiaux dans la régulation des relations entre les producteurs et les chapardeurs. J'ai développé à partir d'une approche d'automate cellulaire un modèle producteur-chapardeur pour déterminer si une règle simple (rule of thumb) fondée sur l'apprentissage social élémentaire dans un contexte spatialement explicite pouvait prédire l'atteinte d'un équilibre producteur-chapardeur. Les résultats démontrent que l'ajout de cette règle simple génère à la fois une flexibilité comportementale significative et des dynamiques complexes qui ne sont pas habituelles à ce genre de systèmes simples. Le modèle lie l'usage d'information sociale à la structure spatiale dans un modèle déterministe. Enfin, avec le cinquième modèle j'ai exploré les effets de la géométrie du paysage (la façon dont l'espace est représenté, habituellement un quadrillage régulier) sur le jeu producteur-chapardeur. Il appert que les représentations spatiales sont un déterminant-clé dans la manière dont un jeu d'approvisionnement social d'alimentation peut réellement rendre compte de l'approvisionnement des animaux. \ud ______________________________________________________________________________ \ud MOTS-CLÉS DE L’AUTEUR : l'approvisionnement social, effets spatiaux, l'utilisation des informations, l'apprentissage, personnalités des animau