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Shared resource extraction among profit-seeking individuals involves a tension between individual benefit and the collective well-being represented by the persistence of the resource. Many game theoretic models explore this scenario, but these models tend to assume either best response dynamics (where individuals instantly switch to better paying strategies) or imitation dynamics (where individuals copy successful strategies from neighbours), and do not systematically compare predictions under the two assumptions. Here we propose an iterated game on a social network with payoff functions that depend on the state of the resource. Agents harvest the resource, and the strategy composition of the population evolves until an equilibrium is reached. The system is then repeatedly perturbed and allowed to re-equilibrate. We compare model predictions under best response and imitation dynamics. Compared to imitation dynamics, best response dynamics increase sustainability of the system, the persistence of cooperation while decreasing inequality and debt corresponding to the Gini index in the agents' cumulative payoffs. Additionally, for best response dynamics, the number of strategy switches before equilibrium fits a power-law distribution under a subset of the parameter space, suggesting the system is in a state of self-organized criticality. We find little variation in most mean results over different network topologies; however, there is significant variation in the distributions of the raw data, equality of payoff, clustering of like strategies and power-law fit. We suggest the primary mechanisms driving the difference in sustainability between the two strategy update rules to be the clustering of like strategies as well as the time delay imposed by an imitation processes. Given the strikingly different outcomes for best response versus imitation dynamics for common-pool resource systems, our results suggest that modellers should choose strategy update rules that best represent decision-making in their study systems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In order to address the topic of the tragedy of the commons, more specifically that of tropical forest ecosystems explored as common-pool resources endowed with public-good features and exposed to deforestation risks, we consider game-theoretic population dynamics contingent on various differential equations. We propose an evolutionary model handed down to the Price theorem of selection. In a set of model-players evolving in strategic uncertainty and subject to certain mutation toward cooperation, the Price equation evens out unstructured and structured population replicator dynamics. According to the model outputs, avoiding the tragedy of the commons can be achieved on condition that half of the population temporarily exhibits a cooperative behavior. Furthermore, cooperative model-players ought to be rewarded at a level equivalent to the joint selection of cooperators and competitors issued from the unifying Price identity.

Fundamental problems of environmental sustainability, including climate change and fisheries management, require collective action on a scale that transcends the political and cultural boundaries of the nation-state. Rational, self-interested neoclassical economic theories of human behavior predict tragedy in the absence of third party enforcement of agreements and practical difficulties that prevent privatization. Evolutionary biology offers a theory of cooperation, but more often than not in a context of discrimination against other groups. That is, in-group boundaries are necessarily defined by those excluded as members of out-groups. However, in some settings human's exhibit behavior that is inconsistent with both rational economic and group driven cooperation of evolutionary biological theory. This paper reports the results of a non-cooperative game-theoretic exercise that models a tragedy of the commons problem in which groups of players may advance their own positions only at the expense of other groups. Students enrolled from multiple universities and assigned to different multi-university identity groups participated in experiments that repeatedly resulted in cooperative outcomes despite intergroup conflicts and expressions of group identity. We offer three possible explanations: (1) students were cooperative because they were in an academic setting; (2) students may have viewed their instructors as the out-group; or (3) the emergence of a small number of influential, ethical leaders is sufficient to ensure cooperation amongst the larger groups. From our data and analysis, we draw out lessons that may help to inform approaches for institutional design and policy negotiations, particularly in climate change management.

We propose a simple two-disease epidemic model where one disease exhibits only a drug-sensitive strain, while the other exhibits both drug-sensitive and drug-resistant strains. Treatment for the first disease may select for resistance in the other. We model antibiotic use as a mathematical game through the study of individual incentives and community welfare. The basic reproduction number is derived and the existence and local stability of the model equilibria are analyzed. When the force of infection of each disease is unaffected by the presence of the other, we find that there is a conflict of interest between individual and community, known as a tragedy of the commons, under targeted treatment toward persons infected by the single strain disease, but there is no conflict under mass treatment. However, we numerically show that individual and social incentive to use antibiotics may show disaccord under mass treatment if the restriction on the transmission ability of the dually infected people is removed, or drug resistant infection is worse than drug sensitive infection, or the uninfected state has a comparative disutility over the infected states., (Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.)

Shrubs are usually adapted to stressful environments in which soil resources are limited, and thus, roots are fundamental for their biological success. However, root measures are challenging to collect, especially in field conditions and at the individual level. For this study, we collected data on the three‐dimensional distribution of fine root biomass of twenty‐three individuals belonging to three shrub species in a mediterranean shrubland in central Spain: gum rockrose Cistus ladanifer, rosemary Salvia rosmarinus, and hairy‐fruited broom Cytisus striatus. Our goal was to determine the soil‐foraging strategies adopted by the plants. We hypothesized that plants would show stabilizing niche differences explaining the high plant biodiversity characteristic of mediterranean shrublands and that they would follow the game theory model's prediction of exploitative segregation of roots behaving territorially but also over‐proliferating roots close to their stem and engaging in a root tragedy of the commons. We found that two‐thirds to three‐fourths of the biomass was belowground, and the system's productivity was roughly 500–600 g C m−2 year−1. Only rosemary plants competed with neighbors following the exploitative segregation predictions. Broom plants had the shallowest and most widespread root systems but significantly reduced their root range toward competing neighbors. Gum rockrose presented deep, narrow root systems avoiding extensive overlap with neighbors but did not appear to respond to competitive pressure levels. Shrubs appeared to stratify their roots at different soil depths, supporting the niche segregation hypothesis. [ABSTRACT FROM AUTHOR]

A significant issue in our world right now, among all others, is climate change. While we are very aware of this issue, our progress toward reducing climate change has been slow. Using game theory, we could make a solid prediction on what we are doing wrong and what we’d need to improve on. But instead, what we want to focus on right now is what the ideal environment would be for the most efficient path to adapting to climate change by using game theory. We found out through simulations that if people cooperate, form strong networks, and work together to find and incorporate solutions, they can prevent and reduce climate change faster. [ABSTRACT FROM AUTHOR]

Climate change mitigation has become a paradigm case both for externalities in general and for the game-theoretic model of the Tragedy of the Commons (ToC) in particular. This situation is worrying, as we have reasons to suspect that some models in the social sciences are apt to be performative to the extent that they can become self-fulfilling prophecies. Framing climate change mitigation as a hardly solvable coordination problem may force us into a worse situation, by changing real-world behaviour to fit our model, rather than the other way around. But while this problem of the performativity of the ToC has been noted in a recent paper in this journal by Matthew Kopec, his proposed strategies for dealing with their self-fulfilling nature fall short of providing an adequate solution. Instead of relying on the idea that modelling assumptions are always strictly speaking false, this paper shows that the problem may be better framed as a problem of underdetermination between competing explanations. Our goal here is to provide a framework for choosing between this set of competing models that allows us to avoid a 'Russian Roulette'-like situation in which we gamble with existential risk. [ABSTRACT FROM AUTHOR]

Flag of convenience (FOC) refers to the practice of registering ships in foreign countries to benefit from lax regulations. While FOC offers several short-term cost advantages to ship owners and FOC countries, it poses significant threats to critical international interests, including environmental protection and marine habitat preservation. Despite global outrage and concerns over FOC's environmental impact, the number of FOC ships have continued to rise. Using game theory, we illustrate how individual rationality – opting for FOC to maximize economic benefits – leads to adverse outcomes for the common good, resulting in increased marine pollution, that we refer to as the tragedy of the commons. Our findings have implications for understanding the strategic behaviour of key players in the maritime transportation, revealing the dark side of globalization and stressing the need for stronger international cooperation to shift these behaviours. • Game theory applied to FOC practices shows how strategic choices for short-term gains lead to the tragedy of the commons. • In this context, the tragedy of the commons refers to increased maritime pollution, resulting in global environmental damage. • FOC practices reveal a dark side of globalization, showing how global market integration can drive unsustainable practices. • Addressing FOC issues needs global collaboration to create robust enforcement mechanisms that align incentives with the greater good. [ABSTRACT FROM AUTHOR]

The productivity of a common pool of resources may degrade when overly exploited by a number of selfish investors, a situation known as the tragedy of the commons. Without regulations, agents optimize the size of their individual investments into the commons by balancing incurring costs with the returns received. The resulting Nash equilibrium involves a self-consistency loop between individual investment decisions and the state of the commons. As a consequence, several non-trivial properties emerge. For N investing actors we prove rigorously that typical payoffs do not scale as 1/N, the expected result for cooperating agents, but as (1/N)2. Payoffs are hence reduced with regard to the functional dependence on N, a situation denoted catastrophic poverty. We show that catastrophic poverty results from a fine-tuned balance between returns and costs. Additionally, a finite number of oligarchs may be present. Oligarchs are characterized by payoffs that are finite and not decreasing when N increases. Our results hold for generic classes of models, including convex and moderately concave cost functions. For strongly concave cost functions the Nash equilibrium undergoes a collective reorganization, being characterized instead by entry barriers and sudden death forced market exits.

Resource sharing is an issue for different fields of applications, giving rise to the so-called “Tragedy of the commons.” This is particularly important in reference to the upcoming Internet of Things, where selfish behaviors from individual users jeopardize system cooperation, on which most network functions rely. We analyze two ways of splitting resources in the context of channel allocation for wireless systems. We describe the outcomes of the different strategies and we identify criteria for the emergence of selfish behaviors in such games. [ABSTRACT FROM AUTHOR]

We propose a simple two-disease epidemic model where one disease exhibits only a drug-sensitive strain, while the other exhibits both drug-sensitive and drug-resistant strains. Treatment for the first disease may select for resistance in the other. We model antibiotic use as a mathematical game through the study of individual incentives and community welfare. The basic reproduction number is derived and the existence and local stability of the model equilibria are analyzed. When the force of infection of each disease is unaffected by the presence of the other, we find that there is a conflict of interest between individual and community, known as a tragedy of the commons, under targeted treatment toward persons infected by the single strain disease, but there is no conflict under mass treatment. However, we numerically show that individual and social incentive to use antibiotics may show disaccord under mass treatment if the restriction on the transmission ability of the dually infected people is removed, or drug resistant infection is worse than drug sensitive infection, or the uninfected state has a comparative disutility over the infected states.

Root competition is a key factor determining plant performance, community structure and ecosystem productivity. To adequately estimate the extent of root proliferation of plants in response to neighbours independently of nutrient availability, one should use a set-up that can simultaneously control for both nutrient concentration and soil volume at plant individual level. With a mesh-divider design, which was suggested as a promising solution for this problem, we conducted two intraspecific root competition experiments: one with soybean (Glycine max) and the other with sunflower (Helianthus annuus). We found no response of root growth or biomass allocation to intraspecific neighbours, i.e. an 'ideal free distribution' (IFD) norm, in soybean; and even a reduced growth as a negative response in sunflower. These responses are all inconsistent with the hypothesis that plants should produce more roots even at the expense of reduced fitness in response to neighbours, i.e. root over-proliferation. Our results suggest that neighbour-induced root over-proliferation is not a ubiquitous feature in plants. By integrating the findings with results from other soybean studies, we conclude that for some species this response could be a genotype-dependent response as a result of natural or artificial selection, or a context-dependent response so that plants can switch from root over-proliferation to IFD depending on the environment of competition. We also critically discuss whether the mesh-divider design is an ideal solution for root competition experiments. [ABSTRACT FROM AUTHOR]

Satellites launched by independent spacefaring agencies and firms create space congestion and collision risk. Taking as benchmark the cost of a marginal reduction of the congestion rate, we discuss tax mechanisms financing a debris removal effort. We compare the non-cooperative equilibrium traffic when there is a tax on each new launch to recover cleanup costs, with the welfare optimal traffic under a centralized tax. We find that under the latter it is twice as easy to recover cleanup costs and increase traffic than under the former. We also show that a linear tax is twice as effective as a quadratic one. [ABSTRACT FROM AUTHOR]

Evolutionary ecological theory suggests that selection arising from interactions with conspecifics, such as sexual and kin selection, may result in evolution of intraspecific conflicts and evolutionary 'tragedy of the commons'. Here, we propose that such an evolution of conspecific conflicts may affect population dynamics in a way that enhances species coexistence. Empirical evidence and theoretical models suggest that more abundant species is more susceptible to invasion of 'selfish' individuals that increase their own reproductive success at the expense of population growth (intraspecific adaptation load). The density-dependent intraspecific adaptation load gives rise to a self-regulation mechanism at the population level, and stabilizes species coexistence at the community level by negative frequency-dependence. Community ecology has suggested that adaptation to environmental conditions (resources and other species) can affect species coexistence. There has been little discussion on how adaptation to intraspecific interactions (sexual and social conflict) affects community dynamics despite its importance in evolutionary ecology. We propose that adaptation to intraspecific conflicts, which often leads to evolution of selfish traits occurring at the expense of population growth (intraspecific adaptation load), can promote species coexistence. It stems from the density-dependent nature of intraspecific adaptation load; it tends to be larger in a larger population and serves as a self-regulating mechanism, which results in negative frequency-dependent growth in community dynamics. We discuss methods for empirically studying intraspecific adaptation load to better link community and evolutionary ecology. [ABSTRACT FROM AUTHOR]

Game theorists tend to model climate negotiations as a so-called 'tragedy of the commons'. This is rather worrisome, since the conditions under which such commons problems have historically been solved are almost entirely absent in the case of international greenhouse gas emissions. In this paper, I will argue that the predictive accuracy of the tragedy model might not stem from the model's inherent match with reality but rather from the model's ability to make self-fulfilling predictions. I then sketch some possible ways to dispel the tragedy, including (1) recognising some ways the assumptions of the model fail, (2) taking seriously recent work suggesting that increasing greenhouse gas emissions is not in most nations' own self-interest, and (3) preferring alternative models like collective risk dilemmas, bargaining games, or cooperative models. [ABSTRACT FROM AUTHOR]

The prisoners' dilemma is a game-theoretical construct about trust. It can be seen as a simple version of the ‘tragedy of the commons’, which is often used in the sustainability context as a metaphor for the tension between responsibility for common resources and the perceived self-benefit to individual organizations, regions or nations who neglect such responsibility in the short term. However, other game theory and developments in sustainability science imply that the prisoners' dilemma mind-set is delusive and misleading for both business and policy making. It helps obscure an even more important aspect of proactive leadership for sustainability: the potential self-benefit of understanding the dynamics of major system change better than one's ‘competitors’ . The UN 1972, 1992, and 2012 summits on sustainability, as well as the many summits on climate change, have been valuable milestones for influencing societal leadership at all levels. However, due to the prisoners' dilemma mind-set, they have also indirectly helped reinforce the idea that sustainability only pays off if the costs of achieving it are shared by all. That, in turn, has encouraged decision makers to believe that ’our organization's, region's or nation's sustainability activity must rely on policy making changing the rules of the game for everybody’. This focus on policy making as the only or main facilitator of sustainability efforts delays the needed transition of global society. By considering game theory such as tit-for-tat and modern systems science for sustainability, this paper illuminates major shortcomings of the prisoners' dilemma in the context of sustainability, and attempts to provide a more fruitful mind-set that can be motivated both theoretically and empirically. It is argued that a large part of the self-benefit of proactivity for sustainability is direct , i.e. independent of other actors' actions for the common good. In addition, it is argued that the self-benefit to businesses can be further increased through voluntary collaboration with other businesses to promote the common good, as well as through collaboration between proactive businesses and policy makers. Currently, none of this is intelligently and operationally part of mainstream leadership and public discourse on sustainability. The clarifications provided in this paper can lead to a much needed shift in mind-set among many leaders, not least political leaders, many of which seem to be trapped in simplistic prisoners' dilemma thinking and who act accordingly. [ABSTRACT FROM AUTHOR]

We analyse active space debris removal efforts from a strategic, game-theoretical perspective. Space debris is non-manoeuvrable, human-made objects orbiting Earth, which pose a significant threat to operational spacecraft. Active debris removal missions have been considered and investigated by different space agencies with the goal to protect valuable assets present in strategic orbital environments. An active debris removal mission is costly, but has a positive effect for all satellites in the same orbital band. This leads to a dilemma: each agency is faced with the choice between the individually costly action of debris removal, which has a positive impact on all players; or wait and hope that others jump in and do the 'dirty' work. The risk of the latter action is that, if everyone waits, the joint outcome will be catastrophic, leading to what in game theory is referred to as the 'tragedy of the commons'. We introduce and thoroughly analyse this dilemma using empirical game theory and a space debris simulator. We consider two- and three-player settings, investigate the strategic properties and equilibria of the game and find that the cost/benefit ratio of debris removal strongly affects the game dynamics. [ABSTRACT FROM AUTHOR]

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La utilización conjunta de un recurso común, generalmente causa su extinción. Esto se conoce como la tragedia de los comunes. En este trabajo se analizan los efectos del aprendizaje adaptativo, usando programación genética, en esta clase de situaciones. En el marco de la teoría de juegos, aquí se considero la interacción estratégica entre los jugadores y la dinámica de un ambiente vinculado fuertemente al juego. Se formuló un modelo de simulación para la situación de los comunes, con base en los resultados de un juego analítico. Posteriormente, se realizó una serie de experimentos computacionales para obtener reglas de juego evolucionadas, las cuales fueron analizadas en relación con los resultados predichos por el modelo analítico. Los resultados obtenidos fueron similares a aquellos predichos por la teoría de juegos clásica, pero no siempre condujeron a una tragedia.

Complex systems exposed to pollution may suddenly and permanently shift to a dangerous regime. This paper studies a dynamic game among countries that face the prospect of such a shift. Each country derives some flow utility from its own emissions, which are chosen unilaterally. But flow emissions by all countries increase the pollution stock in the world. In addition to generating global damages such as global warming, the pollution stock may trigger an irreversible and abrupt jump in global damages or catastrophe at an unknown date in the future. We ask whether endogenous and exogenous threats of such a jump in damages or catastrophe mitigate the tragedy of the commons and examine their implications on welfare. Our analysis yields different emission responses to these threats as compared to the related literature that focuses only on the single-polluter case. For example, when the hazard rate is exogenous and countries commit to nonlinear strategies, we find that the threat of a possible jump in damages or catastrophe may induce a lower or larger emission level and initial welfare due to multiple equilibria. These results are maintained when the hazard rate endogenously depends on emission decisions. [ABSTRACT FROM AUTHOR]

Changes in resource availability often cause competitively driven changes in tree allocation to foliage, wood, and fine roots, either via plastic changes within individuals or through turnover of individuals with differing strategies. Here, we investigate how optimally competitive tree allocation should change in response to elevated atmospheric CO2 along a gradient of nitrogen and light availability, together with how those changes should affect carbon storage in living biomass. We present a physiologically-based forest model that includes the primary functions of wood and nitrogen. From a tree's perspective, wood is an offensive and defensive weapon used against neighbors in competition for light. From a biogeochemical perspective, wood is the primary living reservoir of stored carbon. Nitrogen constitutes a tree's photosynthetic machinery and the support systems for that machinery, and its limited availability thus reduces a tree's ability to fix carbon. This model has been previously successful in predicting allocation to foliage, wood, and fine roots along natural productivity gradients. Using game theory, we solve the model for competitively optimal foliage, wood, and fine root allocation strategies for trees in competition for nitrogen and light as a function of CO2 and nitrogen mineralization rate. Instead of down-regulating under nitrogen limitation, carbon storage under elevated CO2 relative to carbon storage at ambient CO2 is approximately independent of the nitrogen mineralization rate. This surprising prediction is a consequence of both increased competition for nitrogen driving increased fine root biomass and increased competition for light driving increased allocation to wood under elevated CO2. [ABSTRACT FROM AUTHOR]

We discuss an analytically tractable discrete-time dynamic game in which a finite number of players extract a renewable resource. We characterize a symmetric Markov-perfect Nash equilibrium of this game and derive a necessary and sufficient condition under which the resource does not become extinct in equilibrium. This condition requires that the intrinsic growth rate of the resource exceeds a certain threshold value that depends on the number of players and on their time-preference rates. [ABSTRACT FROM AUTHOR]

Purpose – The purpose of this study is to explore potential reasons that might explain why locally owned tourism firms cheat the use of backward economic linkages that (when used) might otherwise maximize the economic benefits of the tourism industry for locals. Design/methodology/approach – For this exploratory qualitative case study research design, 25 face-to-face interviews were conducted with various tourism business owners and managers in Puntarenas, Costa Rica. Findings – The findings indicate that while the participants felt that tourism business' economies of scale could be improved if all locally owned businesses purchased within the tourism supply chain they themselves were purchasing outside of the supply chain. This behavior was characterized as a result of a non-cooperative market. Research limitations/implications – The major implication from the study is a trend that emerged from the data that seems to detect a tragedy of the commons scenario that is rooted in game theory. This scenario provides insight into a problem where tourism business owners and managers indicate an understanding of the value of using local network linkages, but instead cheat the system. A limitation of the study is that case studies may only be generalized to theoretical propositions and not to similar contextual situations. Originality/value – Mainstream tourism literature has provided quantitative assessments that determine the direct, indirect, induced, and multiplier effects of local links between industries, sectors, and different producers that are used in the tourism supply chain. Findings from these studies indicate that local areas economically benefit when these links are actively used. However, not extensively addressed is identification of why (when most individuals know they may all benefit from the use of said linkages) cheat the system. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal symbiosis is omnipresent in boreal forests, where it is assumed to benefit plant growth. However, experiments show inconsistent benefits for plants and volatility of individual partnerships, which calls for a re-evaluation of the presumed role of this symbiosis., We reconcile these inconsistencies by developing a model that demonstrates how mycorrhizal networking and market mechanisms shape the strategies of individual plants and fungi to promote symbiotic stability at the ecosystem level., The model predicts that plants switch abruptly from a mixed strategy with both mycorrhizal and nonmycorrhizal roots to a purely mycorrhizal strategy as soil nitrogen availability declines, in agreement with the frequency distribution of ectomycorrhizal colonization intensity across a wide-ranging data set. In line with observations in field-scale isotope labeling experiments, the model explains why ectomycorrhizal symbiosis does not alleviate plant nitrogen limitation. Instead, market mechanisms may generate self-stabilization of the mycorrhizal strategy via nitrogen depletion feedback, even if plant growth is ultimately reduced., We suggest that this feedback mechanism maintains the strong nitrogen limitation ubiquitous in boreal forests. The mechanism may also have the capacity to eliminate or even reverse the expected positive effect of rising CO2 on tree growth in strongly nitrogen-limited boreal forests. [ABSTRACT FROM AUTHOR]

Groundwater is the natural resource most extracted in the world. It supplies 50% of the total potable water requirements, 40% of the industry take, and 20% of agriculture groundwater is a strategic resource for every country. That common-pool resources are highly susceptible to lead to a tragedy of the commons is a well-known fact. We claim that a combination of groundwater modeling, optimization, and a game theoretical analysis may in fact avoid the tragedy. A groundwater model in MODFLOW from Zamora aquifer in Mexico was used as input of a basic but instructive, optimization problem: extract the greatest possible volume of water, but at the same time minimizing the drawdown and drawdown velocity. The solutions of the optimization problem were used to construct the payoffs of a hypothetical game among the aquifer users, the resource's administrator, and a resource protector entity. We show that the success of the optimal management program depends heavily on the information that the users have about the resource. Therefore, better decision-making processes are a consequence of sustainability literacy. Particularly, water literacy could lead to the usage of water considering it as a part of an ecosystem and not only as a natural resource. Additionally, a new non-classical equation for underground flow was derived, that may be specially important to understand and predict the groundwater flow in highly heterogeneous conditions as in karstic aquifers or fractured media. © 2013 Wiley Periodicals, Inc. Complexity 19: 9-21, 2013 [ABSTRACT FROM AUTHOR]

Game theoretical models predict that plant competition for light leads to reduced productivity of vegetation stands through selection for traits that maximize carbon gains of individuals. Using empirical results from a 5-year competition experiment with 10 genotypes of the clonal plant Potentilla reptans, we tested this prediction by analyzing the effects of the existing leaf area values on the carbon gain of the different genotypes and the consequent whole canopy carbon gain. We focused on specific leaf area (SLA) due to its role in the trade-off between light capture area and photosynthetic capacity per unit area. By combining a canopy model based on measured leaf area and light profiles with a game theoretical approach, we analyzed how changes in the SLA affected genotypic and whole-stand carbon gain. This showed that all genotypes contributed to reduced stand productivity. The dominant genotype maximized its share of total carbon gain, resulting in lower than maximal absolute gain. Other genotypes did not maximize their share. Hypothetical mutants of the dominant genotype were not able to achieve a higher carbon gain. Conversely, in other genotypes, some mutations did result in increased carbon gain. Hence, genotypic differences in the ability to maximize performance may determine genotype frequency. It shows how genotypic selection may result in lower carbon gains of the whole vegetation, and of the individual genotypes it consists of, through similar mechanisms as those that lead to the tragedy of the commons. [ABSTRACT FROM AUTHOR]

The article analyzes the undefined status of efficacy under Section 3(d) of the Indian Patents Act of 1970 from the law and economics perspective of the pharmaceutical industry in India. It states that undefined status of the concept has social welfare implications in the pharmaceutical patents such as arbitrariness, legal uncertainty and corruption, and misapplication. It also calls for a reform in the patent legislation not only in the country but also globally.

Twenty years after the declarations from the Earth Summit in Rio, the world faces an unattenuated host of problems that threaten the goal of sustainable development. The challenge to cooperatively solve socio-ecological problems has been portrayed in Garrett Hardin's essay "The Tragedy of the Commons". While this paper remains controversial, it has inspired a vast number of theoretical, experimental, and empirical contributions that have clarified the mechanisms of collective action problems and suggested ways to overcome these. This article reviews the recent game-theoretic research in this field. [ABSTRACT FROM AUTHOR]

Abstract: Conservation problems typically involve groups with competing objectives and strategies. Taking effective conservation action requires identifying dependencies between competing strategies and determining which action optimally achieves the appropriate conservation goals given those dependencies. We show how several real-world conservation problems can be modeled game-theoretically. Three types of problems drive our analysis: multi-national conservation cooperation, management of common-pool resources, and games against nature. By revealing the underlying structure of these and other problems, game-theoretic models suggest potential solutions that are often invisible to the usual management protocol: decision followed by monitoring, feedback and revised decisions. The kind of adaptive management provided by the game-theoretic approach therefore complements existing adaptive management methodologies. [Copyright &y& Elsevier]

In the game theory literature, Garrett Hardin’s famous allegory of the “tragedy of the commons” has been modeled as a variant of the Prisoner’s Dilemma, labeled the Herder Problem (or, sometimes, the Commons Dilemma). This brief paper argues that important differences in the institutional structures of the standard Prisoner’s Dilemma and Herder Problem render the two games different in kind. Specifically, institutional impediments to communication and cooperation that ensure a dominant strategy of defection in the classic Prisoner’s Dilemma are absent in the Herder Problem. Their absence does not ensure that players will achieve a welfare-enhancing, cooperative solution to the Herders Problem, but does create far more opportunity for players to alter the expected payoffs through cooperative arrangements. In a properly modeled Herder Problem—along the lines of an assurance game—defection would not always be the dominant strategy. Consequently, the Herder Problem is not in the nature of a Prisoner’s Dilemma. [ABSTRACT FROM AUTHOR]

Background and Aims: Game theoretical models predict that plants growing in dense stands invest so much biomass in height growth that it trades-off with investment in other organs such as the leaves, leading to decreased plant production. Using the stoloniferous plant Potentilla reptans, we tested the hypothesis that genotypes investing more in the petioles in response to increased density show a greater decrease in total plant mass. We also tested whether a greater increase in mother ramet investment would lead to a greater decrease in investment in vegetative propagation. [ABSTRACT FROM PUBLISHER]