Cooperation and antagonism in information exchange in a growth scenario with two species

© 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This is a pre-copyedited, author-produced PDF of an article accepted for publication in Journal of Theoretical Biology following peer review. The version of record [Andres Burgos & Daniel Polani, 'Cooperation and antagonism in information exchange in a growth scenario with two species' Journal of Theoretical Biology, Vol 399 (117-133), June 2016] is available on line via doi: http://dx.doi.org/10.1016/j.jtbi.2016.04.006We consider a simple information-theoretic model of communication, in which two species of bacteria have the option of exchanging information about their environment, thereby improving their chances of survival. For this purpose, we model a system consisting of two species whose dynamics in the world are modelled by a bet-hedging strategy. It is well known that such models lend themselves to elegant information-theoretical interpretations by relating their respective long-term growth rate to the information the individual species has about its environment. We are specifically interested in modelling how this dynamics are affected when the species interact cooperatively or in an antagonistic way in a scenario with limited resources. For this purpose, we consider the exchange of environmental information between the two species in the framework of a game. Our results show that a transition from a cooperative to an antagonistic behaviour in a species results as a response to a change in the availability of resources. Species cooperate in abundance of resources, while they behave antagonistically in scarcity.Peer reviewedFinal Accepted Versio

Evaluating the symbiosis status of tourist towns: The case of Guizhou Province, China

This study examines the symbiosis status of tourist towns by analyzing the dynamism between two subsystems of tourist town development: the town subsystem and the tourism subsystem. Drawing on the Lotka-Volterra model, we first developed a model for evaluating the status of harmonious symbiosis development for tourist towns, and then formulated a set of indicators to measure the key components in the model. An empirical study applying the model was conducted focusing on 18 tourist towns in Guizhou Province, China. Recommendations were proposed for more harmonious development of the tourist towns. This is among the first tourism studies that adopt the symbiosis systems approach and our proposed model provides fresh insights into tourist town development

Cooperation Enhances Robustness of Coexistence in Spatially Structured Consortia

Designing synthetic microbial consortia is an emerging area in synthetic biology and a major goal is to realize stable and robust coexistence of multiple species. Cooperation and competition are fundamental intra/interspecies interactions that shape population level behaviors, yet it is not well-understood how these interactions affect the stability and robustness of coexistence. In this paper, we show that communities with cooperative interactions are more robust to population disturbance, e.g., depletion by antibiotics, by forming intermixed spatial patterns. Meanwhile, competition leads to population spatial heterogeneity and more fragile coexistence in communities. Using reaction-diffusion and nonlocal PDE models and simulations of a two-species E. coli consortium, we demonstrate that cooperation is more beneficial than competition in maintaining coexistence in spatially structured consortia, but not in well-mixed environments. This also suggests a tradeoff between constructing heterogeneous communities with localized functions and maintaining robust coexistence. The results provide general strategies for engineering spatially structured consortia by designing interspecies interactions and suggest the importance of cooperation for biodiversity in microbial community

Nutrient dependent cross-kingdom interactions: Fungi and bacteria from an oligotrophic desert oasis

Microbial interactions play a key role in ecosystem functioning, with nutrient availability as an important determinant. Although phylogenetically distant bacteria and fungi commonly co-occur in nature, information on their cross-kingdom interactions under unstable, extreme environments remains poor. Hence, the aims of this work were to evaluate potential in vitro interactions among fungi and bacteria isolated from a phosphorous oligotrophic aquatic system in the Cuatro Ciénegas Basin, Mexico, and to test the nutrients-based shifts. We assessed growth changes in bacteria (Aeromonas and Vibrio) and fungi (Coprinellus micaceus, Cladosporium sp., and Aspergillus niger) on co-cultures in relation to monocultures under diverse nutrient scenarios on Petri dishes. Interactions were explored using a network analysis, and a metabolome profiling for specific taxa. We identified nutrient-dependent patterns, as beneficial interactions dominated in low-nutrients media and antagonistic interactions dominated in rich media. This suggests that cross-kingdom synergistic interactions might favor microbial colonization and growth under low nutrient conditions, representing an adaptive trait to oligotrophic environments. Moreover, our findings agree with the stress-gradient hypothesis, since microbial interactions shifted from competition to cooperation as environmental stress (expressed as low nutrients) increased. At a functional level consistent differences were detected in the production of secondary metabolites, agreeing with plate bioassays. Our results based on culture experiments, provides evidence to understand the complexity of microbial dynamics and survival in phosphorous-depleted environments

The Benefits of Mutualism: A Conceptual Framework

There are three general mechanisms by which phenotypic benefits are transferred between unrelated organisms. First, one organism may purloin benefits from another by preying on or parasitizing the other organism. Second, one organism may enjoy benefits that are incidental to or a by-product of the self-serving traits of another organism. Third, an organism may invest in another organism if that investment produces return benefits which outweigh the cost of the investment. Interactions in which both parties gain a net benefit are mutualistic. The three mechanisms by which benefits are transferred between organisms can be combined in pairs to produce six possible kinds of original or ‘basal’ mutualisms that can arise from an amutualistic state. A review of the literature suggests that most or all interspecific mutualism have origins in three of the six possible kinds of basal mutualism. Each of these three basal mutualisms have byproduct benefits flowing in at least one direction. The transfer of by-product benefits and investment are common to both intra- and interspecific mutualisms, so that some interspecific mutualisms have intraspecific analogs. A basal mutualism may evolve to the point where each party invests in the other, sometimes obscuring the nature of the original interaction along the way. Two prominent models for the evolution of mutualism do not include by-product benefits: Roughgarden's model for the evolution of the damsel-fish anemone mutualism and the ‘Tit-for-Tat’ model of reciprocity. Using the conceptual framework presented here, including in particular by-product benefits, I have shown how it is possible to construct more parsimonious alternatives to both models.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72439/1/j.1469-185X.1995.tb01196.x.pd

Institutional thickening and innovation: reflections on the remapping of the Great Bear Rainforest

The information, practices and views in this article are those of the author(s) and do not necessarily reflect the opinion of the Royal Geographical Society (with IBG). © 2016 Royal Geographical Society (with the Institute of British Geographers) As a response to forest conflict, contemporary remapping refers to re-evaluations of resource values, new and diverse forms of governance among stakeholders, and compromises within patterns of land use that give greater emphasis to environmental and cultural priorities. This paper elaborates the processes of remapping by examining the role of institutional innovation in conflict resolution, with particular reference to the iconic Great Bear Rainforest of British Columbia. After years of conflict and protest, peace in the Great Bear Rainforest was heralded by an interim agreement in 2006, with final ratification likely in 2016. Conceptually, a four-legged stakeholder model identifies the main institutional interests and their interactions through learning and bargaining. New forms of governance were created to bring the stakeholders together in constructive dialogue and then to reach and implement acceptable bargains. Analytically, the paper examines how this agreement has worked in practice by reflecting on the emergence of novel institutions that integrate the interests of key stakeholders. The discussion identifies six bilateral negotiations between: industrial and environmental interests; federal and provincial governments and aboriginal peoples; government and environmental interests; government and industry; industry and aboriginal peoples; and environmental groups and local communities. The remapping process has produced a thickening architecture of institutions that remain experimental even as they seek to promote sustainability, resilience and legitimacy

Oceanus.

v. 34, no. 2 (1991

Nietzschean will to power and the politics of personalities in public diplomacy

The task of understanding and perfecting international and diplomatic relations is becoming more crucial, given the frequency of political disputes and intimidation via public diplomacy. At the root of this trend is the dominance of political personalities in international relations, dictating the direction and progress of conflict control on the international scene. With increasing technological, biological, chemical and nuclear weaponry, ignorance of and any mistaken decision on the diplomatic terrain can come at a huge cost of war and anarchy. At the heart of personalities and human relations, however, Nietzsche argues, is the will to power, that singular striving of each individual to assert his individuality and uniqueness, most times, to the detriment of collective interest. The objective of this paper is to expose what Nietzsche means by will to power in order to allow us have a handle on its influence on politics and social relations. The research question, therefore, addresses the relationship between will to power and the nature of political relationships in public diplomacy. The paper will achieve this by an expository and analytical method of research. The paper finds out that it is apposite that we gain control over the tendency for political persons to exploit public diplomacy to dastardly ends. This is to prevent a consequent descent into anarchy, one that Hobbes describes in grotesque clarity as the war of everyone against everyone, with life being “nasty, brutish and short.

Information-Theoretic Models of Communication in Biological Systems

This thesis aims to find general principles governing the behaviour of biological systems, with a particular emphasis in the communicational (social) aspect of these systems. Communication between biological entities plays a major role in their evolution, enabling them to exchange information about their environment and thereby improving their chances of survival. Communication also plays a pivotal role in the organisation of populations of organisms, clearly observed in social insects, but present also at least in bacteria, plants, fungi, animals and humans. It is also theorised that the genetic code is a by-product of the establishment of an innovation-sharing protocol between primitive cells [Vetsigian et al., 2006]. This thesis is mainly concerned with identifying necessary conditions for the emergence of communicational codes, and the problems that arise with their establishment. For this purpose, we introduce an information-theoretic framework where species maximise their growth rate by following a Kelly-gambling strategy to bet on environmental conditions. Information theory provides a powerful tool for abstracting away mechanisms and for focusing on hard limits of a system's dynamics which cannot be circumvented. We begin by exploring the relation between information exchange and limited resources. We show that a transition from cooperation to antagonism in the exchange of environmental information follows from a change in the availability of resources, from abundant to scarce. We then assume a non-competitive scenario with abundance of resources, where conflicts in a population occur only at a communicational (informational) level, rather than on the physical level, such as competing for (physical) resources. However, traditional Shannon communication is non-semantic, as opposed to the semantic communication observed in biological systems, which is necessary for capturing conflicts in communication. In the traditional use of information theory, it is assumed that every organism knows how to \interpret" the information offered by other organisms. However, this assumes that one \knows" which other organisms one observes, and thus which code they use. In our model, however, we wish to preclude that: namely, we will do away with the assumption that the identity of the organisms who send the messages and those who receive them is known, and the resulting usable information is therefore influenced by the universality of the code used and by which organisms an organism is \listening" to. We introduce a model which captures semantic communication in information-theoretic terms, where organisms talk to each other in a communication network. We show that, for particular population structures, when organisms cannot identify which other organisms they talk to, the adoption of a universal code emerges as a solution for full interpretation of the shared information. However, the evolution and establishment of universal codes for communication introduces vulnerabilities: organisms can be exploited by parasites. We de ne two types of parasites whose strategies have different levels of complexity and study the co-evolution of a host (the population) and a parasite by optimising their respective objective functions in stages. First, we consider a disruptive parasite (a troll) that inflicts harm in a host by minimising a population's mutual understanding, and then a more complex parasite, which manipulates the members of the population via their codes (the puppetmaster). We show emergent characterisations of both parasites, as well as which host configurations are robust against parasites and show adaptive properties. This thesis introduces a framework which allows the study of informational properties in the host-parasite co-evolution, where the rules of the parasite's habitat, the host, are the outcome of an evolutionary process, and where these very same rules are those that allow the parasite to exploit the host

The Commons

"This book explores the potential creation of a broader collaborative economy through commons-based peer production (P2P) and the emergent role of information and communication technologies (ICTs). The book seeks to critically engage in the political discussion of commons-based peer production, which can be classified into three basic arguments: the liberal, the reformist and the anti-capitalist. This book categorises the liberal argument as being in favour of the coexistence of the commons with the market and the state. Reformists, on the other hand, advocate for the gradual adjustment of the state and of capitalism to the commons, while anti-capitalists situate the commons against capitalism and the state. By discussing these three viewpoints, the book contributes to contemporary debates concerning the future of commons-based peer production. Further, the author argues that for the commons to become a fully operational mode of peer production, it needs to reach critical mass arguing that the liberal argument underestimates the reformist insight that technology has the potential to decentralise production, thereby forcing capitalism to transition to post-capitalism. Surveying the three main strands of commons-based peer production, this book makes the case for a post-capitalist commons-orientated transition that moves beyond neoliberalism.