Memory-Based Snowdrift Game on Networks

We present a memory-based snowdrift game (MBSG) taking place on networks. We found that, when a lattice is taken to be the underlying structure, the transition of spatial patterns at some critical values of the payoff parameter is observable for both 4 and 8-neighbor lattices. The transition points as well as the styles of spatial patterns can be explained by local stability analysis. In sharp contrast to previously reported results, cooperation is promoted by the spatial structure in the MBSG. Interestingly, we found that the frequency of cooperation of the MBSG on a scale-free network peaks at a specific value of the payoff parameter. This phenomenon indicates that properly encouraging selfish behaviors can optimally enhance the cooperation. The memory effects of individuals are discussed in detail and some non-monotonous phenomena are observed on both lattices and scale-free networks. Our work may shed some new light on the study of evolutionary games over networks.Comment: 6 pages, 6 figures, to be published in Phys. Rev.

Do people really want to be nudged towards healthy lifestyles?

This paper assesses Thaler and Sunstein’s claim that policies that nudge individuals towards healthy lifestyles promote the welfare of those individuals, as judged by themselves. I argue that Thaler and Sunstein switch between two different interpretations of that clause. One interpretation gives the clause a wide range of applicability, but drains it of its content as a repudiation of paternalism. The other interpretation makes it more meaningful to say that people want to make the choices they are being nudged towards, but applies to a much narrower range of cases than Thaler and Sunstein have in mind

Networking Effects on Cooperation in Evolutionary Snowdrift Game

The effects of networking on the extent of cooperation emerging in a competitive setting are studied. The evolutionary snowdrift game, which represents a realistic alternative to the well-known Prisoner's Dilemma, is studied in the Watts-Strogatz network that spans the regular, small-world, and random networks through random re-wiring. Over a wide range of payoffs, a re-wired network is found to suppress cooperation when compared with a well-mixed or fully connected system. Two extinction payoffs, that characterize the emergence of a homogeneous steady state, are identified. It is found that, unlike in the Prisoner's Dilemma, the standard deviation of the degree distribution is the dominant network property that governs the extinction payoffs.Comment: Changed conten

Preference purification and the inner rational agent:A critique of the conventional wisdom of behavioural welfare economics

Neoclassical economics assumes that individuals have stable and context-independent preferences, and uses preference-satisfaction as a normative criterion. By calling this assumption into question, behavioural findings cause fundamental problems for normative economics. A common response to these problems is to treat deviations from conventional rational-choice theory as mistakes, and to try to reconstruct the preferences that individuals would have acted on, had they reasoned correctly. We argue that this preference purification approach implicitly uses a dualistic model of the human being, in which an inner rational agent is trapped in an outer psychological shell. This model is psychologically and philosophically problematic

A dynamically extending exclusion process

An extension of the totally asymmetric exclusion process, which incorporates a dynamically extending lattice is explored. Although originally inspired as a model for filamentous fungal growth, here the dynamically extending exclusion process (DEEP) is studied in its own right, as a nontrivial addition to the class of nonequilibrium exclusion process models. Here we discuss various mean-field approximation schemes and elucidate the steady state behaviour of the model and its associated phase diagram. Of particular note is that the dynamics of the extending lattice leads to a new region in the phase diagram in which a shock discontinuity in the density travels forward with a velocity that is lower than the velocity of the tip of the lattice. Thus in this region the shock recedes from both boundaries.Comment: 20 pages, 12 figure

Characterising competitive equilibrium in terms of opportunity

This paper analyses alternative profiles of opportunity sets for individuals in an exchange economy, without assuming that individuals’ choices reveal coherent preferences. It introduces the concept of a ‘market-clearing single-price regime’, representing a profile of opportunity sets consistent with competitive equilibrium. It also proposes an opportunity-based normative criterion, the Strong Opportunity Criterion, which is analogous with the core in preference-based analysis. It shows that every market-clearing single-price regime satisfies the Strong Opportunity Criterion and that, in the limit as an economy is replicated, only such regimes have this property

Proprietary Reasons and Joint Action

Some of the reasons one acts on in joint action are shared with fellow participants. But others are proprietary: reasons of one’s own that have no direct practical significance for other participants. The compatibility of joint action with proprietary reasons serves to distinguish the former from other forms of collective agency; moreover, it is arguably a desirable feature of joint action. Advocates of “team reasoning” link the special collective intention individual participants have when acting together with a distinctive form of practical reasoning that purports to put individuals in touch with group or collective reasons. Such views entail the surprising conclusion that one cannot engage in joint action for proprietary reasons. Suppose we understand the contrast between minimal and robust forms of joint action in terms of the extent to which participants act on proprietary reasons as opposed to shared reasons. Then, if the team reasoning view of joint intention and action is correct, it makes no sense to talk of minimal joint action. As soon as the reason for which one participates is proprietary, then one is not, on this view, genuinely engaged in joint action

Nuclear Dbf2-related protein kinases (NDRs) in isolated cardiac myocytes and the myocardium: activation by cellular stresses and by phosphoprotein serine-/threonine-phosphatase inhibitors

The nuclear Dbf2-related protein kinases 1 and 2 (NDR1/2) are closely-related AGC family kinases that are strongly conserved through evolution. In mammals, they are activated inter alia by phosphorylation of an hydrophobic domain threonine-residue [NDR1(Thr-444)/NDR2(Thr-442)] by an extrinsic protein kinase followed by autophosphorylation of a catalytic domain serine-residue [NDR1(Ser-281)/NDR2(Ser-282)]. We examined NDR1/2 expression and regulation in primary cultures of neonatal rat cardiac myocytes and in perfused adult rat hearts. In myocytes, transcripts for NDR2, but not NDR1, were induced by the hypertrophic agonist, endothelin-1. NDR1(Thr-444) and NDR2(Thr-442) were rapidly phosphorylated (maximal in 15-30 min) in myocytes exposed to some phosphoprotein Ser-/Thr-phosphatase 1/2 inhibitors (calyculin A, okadaic acid) and, to a lesser extent, by hyperosmotic shock, low concentrations of H(2)O(2), or chelerythrine. In myocytes adenovirally-transduced to express FLAG-NDR2 (which exhibited a mainly-cytoplasmic localisation), the same agents increased FLAG-NDR2 activity as assessed by in vitro protein kinase assays, indicative of FLAG-NDR2(Ser-282/Thr-442) phosphorylation. Calyculin A-induced phosphorylation of NDR1(Thr-444)/NDR2(Thr-442) and activation of FLAG-NDR2 were inhibited by staurosporine, but not by other protein kinase inhibitors tested. In ex vivo rat hearts, NDR1(Thr-444)/NDR2(Thr-442) were phosphorylated in response to ischaemia-reperfusion or calyculin A. From a pathological viewpoint, we conclude that activities of NDR1 and NDR2 are responsive to cytotoxic stresses in heart preparations and this may represent a previously-unidentified response to myocardial ischaemia in vivo

A model of hyphal tip growth involving microtubule-based transport

We propose a simple model for mass transport within a fungal hypha and its subsequent growth. Inspired by the role of microtubule-transported vesicles, we embody the internal dynamics of mass inside a hypha with mutually excluding particles progressing stochastically along a growing one-dimensional lattice. The connection between long range transport of materials for growth, and the resulting extension of the hyphal tip has not previously been addressed in the modelling literature. We derive and analyse mean-field equations for the model and present a phase diagram of its steady state behaviour, which we compare to simulations. We discuss our results in the context of the filamentous fungus, Neurospora crassa.Comment: 5 pages, 5 figure

‘I don't think I can catch it’: women, confidence and responsibility in football coach education

Whilst women’s participation in sport continues to increase, their presence remains ideologically challenging given the significance of sport for the construction of gendered identities. As a hegmonically masculine institution, leadership roles across sport remain male-dominated and the entry of women into positions of authority (such as coaching) routinely contested. But in powerful male-typed sports, like football, women’s participation remains particularly challenging. Consequently, constructions of gender inequity in coaching were explored at a regional division of the English Football Association through unstructured interviews and coaching course observation. Using critical discourse analysis we identified the consistent re/production of women as unconfident in their own skills and abilities, and the framing of women themselves as responsible for the gendered inequities in football coaching. Women were thereby strategically positioned as deservedly on the periphery of the football category,whilst the organization was positioned as progressive and liberal