Defection or Cooperation—Richard Power’s Moral Insights in Prisoner’s Dilemma

Prisoner’s Dilemma is a master trope for relaying the permanent impasse or dilemma of cooperation versus defection.In Prisoner’s Dilemma Richard Powers narrates a multiform of dilemma mainly narrating Eddie Hobson’s traumatic history,along with Eddie’s attempt to carry out a strategy—Eddie’s ideal Hobstown which is supposed to cope with the confused dilemma.Pow⁃ers’strategic moral insights are revealed by assuming that each player feels sympathy for the other and a moral cooperative instead of antagonistic solution to the Prisoner’s Dilemma will be found.

Richard Power’s Philosophical Thoughts in Prisoner’s Dilemma

The“prisoner’s dilemma”illustrates that everyone is rationally thinking about maximizing their own interests and taking their own best strategies,but the end result is counterproductive.In Prisoner’s Dilemma Richard Powers describes multiformareas of dilemma;to lose balance;to make choices;and ask each other:what to do next?It is a master trope for relaying the permanent impasse or dilemma of cooperation versus defection.In most cases,the prisoner's dilemma is more about the number of defeats in the game,and even a major loss of society.Individual rationality is likely to be a collective disregard,and if everyone is acting on the principle of self-interest,it is often the result that everyone is lost.Powers expresses his philosophical insight:Until a cooperative instead of antagonistic solution is collectively agreed upon,we still remain imprisoned in an interminable and oppressive struggle and conflict decided by self-interest and rational control,which is also a moral response to historical consciousness of postmodernism.

Protect Sick Prisoners' Rights Through Regulation and Innovation——Chengdu launches coordinating mechanism for sick prisoners with major diseases

In May 2011, the Prison Management Bureau of Sichuan Province in Southwest China held a conference in its capital city Chengdu to discuss the management of severely sick prisoners. Coordinating Management on Major Diseases of Sick Prisoners in Sichuan （Trial） was issued then, marking the start of an overall deployment.

Intentional ingestions of foreign objects among prisoners: A review

The intentional ingestion of foreign objects(IIFO) is described more commonly in prison populations than in the general population, with an estimated annual incidence of 1 in 1900 inmates in our state correctional facilities. Incidents often involve ingestion of small metal objects(e.g., paperclips, razor blades) or other commonly available items like pens or eating utensils. Despite ingestion of relatively sharp objects, most episodes can be clinically managed with either observation or endoscopy. Surgery should be reserved for those with signs or symptoms of gastrointestinal perforation or obstruction. For those with a history of IIFO, efforts should focus on prevention of recurrenceas subsequent episodes are associated with higher morbidity, significant healthcare and security costs. The pattern of IIFO is often repetitive, with escalation both in frequency of ingestions and in number of items ingested. Little is known about successful prevention strategies, but efforts to monitor patients and provide psychiatric care are potential best-practice strategies. This article aims to provide state-of-the art review on the topic, followed by a set of basic recommendations.

An Adaptive Strategy via Reinforcement Learning for the Prisoner＇s Dilemma Game

The iterated prisoner's dilemma(IPD) is an ideal model for analyzing interactions between agents in complex networks. It has attracted wide interest in the development of novel strategies since the success of tit-for-tat in Axelrod's tournament. This paper studies a new adaptive strategy of IPD in different complex networks, where agents can learn and adapt their strategies through reinforcement learning method. A temporal difference learning method is applied for designing the adaptive strategy to optimize the decision making process of the agents. Previous studies indicated that mutual cooperation is hard to emerge in the IPD. Therefore, three examples which based on square lattice network and scale-free network are provided to show two features of the adaptive strategy. First, the mutual cooperation can be achieved by the group with adaptive agents under scale-free network, and once evolution has converged mutual cooperation, it is unlikely to shift. Secondly, the adaptive strategy can earn a better payoff compared with other strategies in the square network. The analytical properties are discussed for verifying evolutionary stability of the adaptive strategy.

Prevalence of hepatitis C virus infection and its related risk factors in drug abuser prisoners in Hamedan-Iran

AIM:Recent studies in Iran has shown that prevalence of hepatitis C virus (HCV) infection among Iranian prisoners is high, in spite of low HCV seroprevalence in general population. METHODS: This study was carried out in the central prison of Hamedan - Iran, in year 2002. Inmates were interviewed using a standard questionnaire including demographic, imprisonment history and HCV-related risk behaviors items. Thereafter, the sera drawn from the participants were tested for anti-HIV and anti-HCV antibodies. RESULTS: A total number of 427 drug abuser inmates participated in our study. Three hundred and ninety-seven (93%) were men and 30 (7%) were women. Total number of IV drug abusers (IDA) and non-IV drug abusers (NIDA) was 149 (34.9%) and 278 (65.1%), respectively. The overall rate of antibody positivity among inmates was 0.9% for HIV and 30% for HCV. Of all IDAs, 31.5% and of NIDAs, 29.1% had serological evidence of HCV infection. CONCLUSION: The seroprevalence of HCV infection among drug abuser prisoners in comparison with the general population in Iran, is very high (30% vs in italics 0.2%). Our results indicate the importance of policies to prevent transmission of HCV infection during and following incarceration.

Hepatitis C virus infection and prisoners: Epidemiology, outcome and treatment

The studies on hepatitis C virus(HCV) infection in prison populations are few and mostly cross-sectional. We analyzed prevalently the articles appearing on Pub Med in the last ten years. HCV infection is frequent in prisoners, prevalences ranging from 3.1% to 38% according to the HCV endemicity in the geographical location of the prison and in the countries of origin of the foreign prisoners and to the prevalence of intravenous drug use, which is the most important risk factor for HCV infection, followed by an older age of prisoners and previous prison terms. HCV replication in anti-HCVpositive cases varies from 45% to 90% in different studies, and the most common HCV genotypes are generally 1 and 3. The response to antiviral treatment is similar in prisoners to that of the general population. Unfortunately, treatment is administered less frequently to prisoners because of the difficulties in management and follow-up. The new directly acting antivirals offer a good therapy option for inmates because of their good efficacy, short duration of treatment and low incidence of side effects. The efforts of the prison authorities and medical staff should be focused on reducing the spread of HCV infection in prisons by extending the possibility of follow-up and treatment to more prisoners with chronic hepatitis C.

THE OPTIMAL CONTROL FOR PROMOTING THE COOPERATION IN EVOLUTION GAME GENERATED BY PRISONER'S DILEMMA

Natural selection opposes the evolution of cooperation unless specific mechanisms are at work in Prisoner＇s Dilemma. By taking advantage of the modern control theory, the controller design is discussed and the optimal control is designed for promoting cooperation based on the recent advances in mechanisms for the evolution of cooperation. Two con- trol strategies are proposed： compensation control strategy for the cooperator when playing against a defector and reward control strategy for cooperator when playing against a coop- erator. The feasibility and effectiveness of these control strategies for promoting cooperation in different stages are analyzed. The reward for cooperation can＇t prevent defection from being evolutionary stable strategy （ESS）. On the other hand, compensation for the coopera- tor can＇t prevent defection from emerging and sustaining. By considering the effect and the cost, an optimal control scheme with constraint on the admissible control set is put forward. By analyzing the special nonlinear system of replicator dynamics, the exact analytic solution of the optimal control scheme is obtained based on the maximum principle. Finally, the effectiveness of the proposed method is illustrated by examples.

Effects of Probability of Revelation of Defection and Penalty to Defection on Cooperative Behavior in 2-Person Prisoner＇s Dilemma Game

In our society, it is a major issue to enhance cooperative behaviors. Without this, our society fall into social dilemma situations, and gets worse and worse. Such a situation in an organization leads to violation of social or organizational rules, and at the worst case it suffers from serious accidents or scandals. Therefore, it is important for organizational managers to make efforts and take measures to enhance cooperative behaviors. Although there seem to be many ways to constantly elicit cooperative behaviors, the punishment is one of the most effective measures for enhancing cooperation. This study focused on the effects of penalty and probability of the revelation of defection on the cooperation, and getting insight into how punishment strategy should be used to get rid of social dilemmas and enhance cooperation. This study conducted a simulation experiment to find the proper penal regulations condition that can suppress violations （defective behavior） in a 2-person prisoner＇s dilemma situation. The effects of probability of the revelation of defection and penalty to revelation on the cooperative behavior were identified with the interactive effect of both experimental factors. The defection （uncooperative behavior） decreased when the penalty to the defection was heavy and the probability of the revelation of defection was low than that when the penalty to the defection was light and the probability of the revelation of the defection was high.

Evolutionary prisoner's dilemma game on highly clustered community networks

This paper studies the evolutionary prisoner＇s dilemma game on a highly clustered community network in which the clustering coefficient and the community size can be tuned. It finds that the clustering coefficient in such a degree-homogeneous network inhibits the emergence of cooperation for the entire range of the payoff parameter. Moreover, it finds that the community size can also have a marked influence on the evolution of cooperation, with a larger community size leading to not only a lower cooperation level but also a smaller threshold of the payoff parameter above which cooperators become extinct.

Prevalence,genotypes and factors associated with HCV infection among prisoners in Northeastern Brazil

AIM： To determine hepatitis C virus （HCV） seropreva- lence and its genotypes, and to identify the factors associated with HCV infection. METHODS： This cross-sectional study, conducted in two prisons （one male and one female） in the State of Ser- gipe, Brazil, comprised 422 subjects. All of the prisoners underwent a rapid test for the detection of HCV antibod- ies. Patient~ with a positive result were tested for anti- HCV by enzyme linked immunosorbent assay and for HCV RNA by qualitative polymerase chain reaction （PCR）. The virus genotype was defined in every serum sample that presented positive for PCR-HCV. In order to determine the factors independently associated with positive serol- ogy for HCV, multivariate logistic regression was used. RESULTS： HCV seroprevalence was 3.1%. Of the 13 subjects with positive anti-HCV, 11 had viremia confirmed by PCR. Of these, 90.9% had genotype 1. A total of 43 （10.2%） were injecting drug users, and HCV seroprevalence in this subgroup was 20.6%. The variable most strongly associated with positive serology for HCV was use of injecting drugs [odds ratio （OR）, 23.3; 95% confidence interval （CI）, 6.0-90.8]. Age over 30 years （OR, 5.5; 95%CI, 1.1-29.2）, history of syphilis （OR, 9.8; 95%CI, 1.7-55.2） and history of household contact with HCV positive individual （OR, 14.1; 95%CI, 2.3-85.4） were also independently associated with HCV infection. CONCLUSION： Most of the HCV transmissions result from parenteral exposure. However, there is evidence to suggest a role for sex and household contact with an infected subject in virus transmission.

Evolutionary prisoner’s dilemma on Newman-Watts social networks with an asymmetric payoff distribution mechanism

In this paper, we introduce an asymmetric payoff distribution mechanism into the evolutionary prisoner＇s dilemma game （PDG） on Newman Watts social networks, and study its effects on the evolution of cooperation. The asymmetric payoff distribution mechanism can be adjusted by the parameter α： if α〉 0, the rich will exploit the poor to get richer; if α 〈 0, the rich are forced to offer part of their income to the poor. Numerical results show that the cooperator frequency monotonously increases with c~ and is remarkably promoted when c~ 〉 0. The effects of updating order and self-interaction are also investigated. The co-action of random updating and self-interaction can induce the highest cooperation level. Moreover, we employ the Gini coefficient to investigate the effect of asymmetric payoff distribution on the the system＇s wealth distribution. This work may be helpful for understanding cooperative behaviour and wealth inequality in society.

PREFERENCE AND EVOLUTION IN THE ITERATED PRISONER'S DILEMMA

Game theory is extensively used to study strategy-making and actions of play- ers. The authors proposed an analysis method for study the evolutionary outcome and behaviors of players with preference in iterated prisoner＇s dilemma. In this article, a preference parameter k was introduced in the payoff matrix, wherein the value of k denotes the player＇s degree of egoism and altruism （preference）. Then, a game-theoretic dynamical model was formulated using Birth-and-Death process. The authors studied how preference influences the evolutionary equilibrium and behaviors of players. The authors get the general results： egoism leads to defection, and altruism can make players build trust and maintain cooperation, and so, the hope of the Pareto optimal solution. In the end, the simulation experiments proved the efficiency of the method.

Prevalence of smear positive pulmonary tuberculosis in Gondar prisoners,North West Ethiopia

Objective:To assess the prevalence and risk factors of smear positive pulmonary tuberculosis among Condar town prisoners.North West Ethiopia.Methods:A cross sectional study was conducted from February to July,2008 in Condar Prison.Prisoners with cough duration of more than two weeks were involved in the study by giving three sputum samples and filling the questionnaires prepared for risk factor assessment.Acid fast staining technique was employed to delect the presence of the Mycobacterium tuberculosis bacilli in the sputum samples.Data was analyzed using SPSS version13 computer software and presented in table.Chi-square test was used to assess associations and a P-value less than 0.05 was taken as significant.Results:A total of 384 prisoners,349 male and 35 females,with a mean age of 33.3 years were involved in the study.The prevalence of smear positive pulmonary tuberculosis among those prisoners with cough duration of more than two wecks was 8.59%.Only the length of imprisonment had a significant association(χ~2= 18.82,P-value【0.0001) with the prevalence of tuberculosis.Conclusions:This study indicated that tuberculosis among prisoners with cough duration of more then two weeks in Gondar prison is very high.Therefore Periodic screening of the prisoners and screening of newly introduced prisoners should be practiced so as to minimise the burden of tuberculosis in prisoners.

Payoff-based accumulative effect promotes cooperation in spatial prisoner’s dilemma

We study the effect of accumulative payoff on the evolution of cooperation in the evolutionary prisoner＇s dilemma on a square lattice. We introduce a decaying factor for the accumulative payoff, which characterizes the extent that the historical payoff is accumulated. It is shown that for fixed values of the temptation to defect, the density of cooperators increases with the value of the decaying factor. This indicates that the more the historical payoff is involved, the more favourable cooperators become. In the critical region where the cooperator density converges to zero, cooperators vanish according to a power-law-like behaviour. The associated exponents agree approximately with the two-dimensional directed percolation and depend weakly on the value of the decaying factor.

Adaptive co-evolution of strategies and network leading to optimal cooperation level in spatial prisoner's dilemma game

We study evolutionary prisoner＇s dilemma game on adaptive networks where a population of players co-evolves with their interaction networks. During the co-evolution process, interacted players with opposite strategies either rewire the link between them with probability p or update their strategies with probability 1 - p depending on their payoffs. Numerical simulation shows that the final network is either split into some disconnected communities whose players share the same strategy within each community or forms a single connected network in which all nodes are in the same strategy. Interestingly, the density of cooperators in the final state can be maximised in an intermediate range of p via the competition between time scale of the network dynamics and that of the node dynamics. Finally, the mean-field analysis helps to understand the results of numerical simulation. Our results may provide some insight into understanding the emergence of cooperation in the real situation where the individuals＇ behaviour and their relationship adaptively co-evolve.

A 2-stage strategy updating rule promotes cooperation in the prisoner's dilemma game

In this study,we propose a spatial prisoner＇s dilemma game model with a 2-stage strategy updating rule,and focus on the cooperation behavior of the system.In the first stage,i.e.,the pre-learning stage,a focal player decides whether to update his strategy according to the pre-learning factor β and the payoff difference between himself and the average of his neighbors.If the player makes up his mind to update,he enters into the second stage,i.e.,the learning stage,and adopts a strategy of a randomly selected neighbor according to the standard Fermi updating rule.The simulation results show that the cooperation level has a non-trivial dependence on the pre-learning factor.Generally,the cooperation frequency decreases as the pre-learning factor increases;but a high cooperation level can be obtained in the intermediate region of- 3〈 β 〈-1.We then give some explanations via studying the co-action of pre-learning and learning.Our results may sharpen the understanding of the influence of the strategy updating rule on evolutionary games.

Effects of Dimers on Cooperation in the Spatial Prisoner's Dilemma Game

We investigate the evolutionary prisoner＇s dilemma game in structured populations by introducing dimers, which are defined as that two players in each dimer always hold a same strategy. We find that influences of dimets on cooperation depend on the type of dimers and the population structure. For those dimers in which players interact with each other, the cooperation level increases with the number of dimers though the cooperation improvement level depends on the type of network structures. On the other hand, the dimers, in which there are not mutual interactions, will not do any good to the cooperation level in a single community, but interestingly, will improve the cooperation level in a population with two communities. We explore the relationship between dimers and self-interactions and find that the effects of dimers are similar to that of self-interactions. Also, we find that the dimers, which are established over two communities in a multi-community network, act as one type of interaction through which information between communities is communicated by the requirement that two players in a dimer hold a same strategy.

Cooperation influenced by the correlation degree of two-layered complex networks in evolutionary prisoner’s dilemma games

An evolutionary prisoner＇s dilemma game is investigated on two-layered complex networks respectively representing interaction and learning networks in one and two dimensions. A parameter q is introduced to denote the correlation degree between the two-layered networks. Using Monte Carlo simulations we studied the effects of the correlation degree on cooperative behaviour and found that the cooperator density nontrivially changes with q for different payoff parameter values depending on the detailed strategy updating and network dimension. An explanation for the obtained results is provided.

Effects of Topological Randomness on Cooperation in a Deterministic Prisoner's Dilemma Game

In this work, we consider an evolutionary prisoner＇s dilemma game on a homogeneous random network with the richest-following strategy adoption rule. By constructing homogeneous random networks from a regular ring graph, we investigate the effects of topologicaJ randomness on cooperation. In contrast to the ordinary view that the presence of smaJ1 amount of shortcuts in ring graphs favors cooperation, we find the cooperation inhibition by weak topological randomness. The explanations on the observations are presented.