Chickens First\ud \ud Speciation by “Hopeful Monsters” in Fraternal Supertwins\ud

The idea of “hopeful monster” was proposed by Goldschmidt who envisioned that speciation could occur instantaneously via major chromosomal rearrangement in a one-step process; but he could not unravel how similar individual in the opposite sex to appear on the same time and location to generate next generation. This paper provides the answer for the challenge. \ud In this paper, a model of speciation in animals is discussed in detail. Only four steps are needed to generate a new species in sexual animals: fraternal twin zygotes, similar gross mutation on the zygotes, self-splitting of mutated zygotes into two groups of identical zygotes of both sexes, development of zygotes with birth of babies, and inbreeding when they mature. The outcome of these steps is generation of new species with chromosomal homozygosity. Viviparous animals (living young not eggs are produced) are used to explain the model. With slight modifications, other asexual organisms could be accommodated. \ud As the model provides the simplest explanation for speciation in all sexual animals, which plausibly explains many puzzles in biology; such as chicken egg, Cambrian explosion, appearance of new organs, etc. The author presents a few predictions that can be falsified. \ud This model needs only one assumption and it is consistent with many well-known observations. \u

A Model of Human Cooperation in Social Dilemmas

Social dilemmas are situations in which collective interests are at odds with private interests: pollution, depletion of natural resources, and intergroup conflicts, are at their core social dilemmas. Because of their multidisciplinarity and their importance, social dilemmas have been studied by economists, biologists, psychologists, sociologists, and political scientists. These studies typically explain tendency to cooperation by dividing people in proself and prosocial types, or appealing to forms of external control or, in iterated social dilemmas, to long-term strategies. But recent experiments have shown that cooperation is possible even in one-shot social dilemmas without forms of external control and the rate of cooperation typically depends on the payoffs. This makes impossible a predictive division between proself and prosocial people and proves that people have attitude to cooperation by nature. The key innovation of this article is in fact to postulate that humans have attitude to cooperation by nature and consequently they do not act a priori as single agents, as assumed by standard economic models, but they forecast how a social dilemma would evolve if they formed coalitions and then they act according to their most optimistic forecast. Formalizing this idea we propose the first predictive model of human cooperation able to organize a number of different experimental findings that are not explained by the standard model. We show also that the model makes satisfactorily accurate quantitative predictions of population average behavior in one-shot social dilemmas

Universal Learning of Repeated Matrix Games

We study and compare the learning dynamics of two universal learning algorithms, one based on Bayesian learning and the other on prediction with expert advice. Both approaches have strong asymptotic performance guarantees. When confronted with the task of finding good long-term strategies in repeated 2x2 matrix games, they behave quite differently.Comment: 16 LaTeX pages, 8 eps figure

Correlated equilibria, good and bad : an experimental study

We report results from an experiment that explores the empirical validity of correlated equilibrium, an important generalization of the Nash equilibrium concept. Specifically, we seek to understand the conditions under which subjects playing the game of Chicken will condition their behavior on private, third–party recommendations drawn from known distributions. In a “good–recommendations” treatment, the distribution we use is a correlated equilibrium with payoffs better than any symmetric payoff in the convex hull of Nash equilibrium payoff vectors. In a “bad–recommendations” treatment, the distribution is a correlated equilibrium with payoffs worse than any Nash equilibrium payoff vector. In a “Nash–recommendations” treatment, the distribution is a convex combination of Nash equilibrium outcomes (which is also a correlated equilibrium), and in a fourth “very–good–recommendations” treatment, the distribution yields high payoffs, but is not a correlated equilibrium. We compare behavior in all of these treatments to the case where subjects do not receive recommendations. We find that when recommendations are not given to subjects, behavior is very close to mixed–strategy Nash equilibrium play. When recommendations are given, behavior does differ from mixed–strategy Nash equilibrium, with the nature of the differ- ences varying according to the treatment. Our main finding is that subjects will follow third–party recommendations only if those recommendations derive from a correlated equilibrium, and further,if that correlated equilibrium is payoff–enhancing relative to the available Nash equilibria

Bargaining and Influence in Conflict Situations

[Excerpt] This chapter examines bargaining as an influence process through which actors attempt to resolve a social conflict. Conflict occurs when two or more interdependent actors have incompatible preferences and perceive or anticipate resistance from each other (Blalock 1989; Kriesberg 1982). Bargaining is a basic form of goal-directed action that involves both intentions to influence and efforts by each actor to carry out these intentions. Tactics are verbal and/or nonverbal actions designed to maneuver oneself into a favorable position vis-a-vis another or to reach some accommodation. Our treatment of bargaining subsumes the concept of negotiation (see Morley and Stephenson 1977). This chapter is organized around a conceptual framework that distinguishes basic types of bargaining contexts. We begin by introducing the framework and then present an overview of and analyze theoretical and empirical work on each type of bargaining context

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter