Inequality, Coalitions and Collective Action

In a model where cooperation is beneficial, but subject to cheating, and is supported by trigger strategy punishments in a repeated game, we explore the relationship between the nature of cooperation (size and composition of coalitions) and underlying inequality in the distribution of private productive assets.

Noise In Nonohmic Regimes Of Disordered Systems

We present here a short review of mainly experimental properties of noise as disordered systems are driven into non-ohmic regimes by applying voltages of few volts only. It is found that the noise does not simply follow the resistance in that the direction of change of noise could be opposite to that of resistance. It is discussed how this and other properties make the noise a complementary and incisive tool for studying complex systems, particularly its dynamic properties. Study of noise in non-ohmic regimes in physical systems is rather in a nascent stage. Some of the open issues are highlighted.Comment: 9 Pages, 7 figures. Reported in Unsolved Problems of Noise and Fluctuations: UPoN 2005, Gallipoli, Italy, June 6-10, 200

Artfilms, Handicrafts and Other Cultural Goods: The Case for Subsidy

Though widespread, the practice of public subsidies for cultural activity lacks a rigorous and consistent economic rationale. We analyze a canonical market structure that characterizes much cultural activity: the competition of mass-produced goods with heterogeneous non- standardized goods that are imperfect substitutes. We analyze several types of market failure: uncertainty about preferences (we do not know what we like, and we do not know what we might like in the future); endogeneity of preferences (we like what our neighbors talk about, and we like what we're accustomed to); and externalities associated with production (future production costs are determined by current production). The model provides a basis for cultural subsidies to promote social welfare and economic development.

Distinguishing Motor Weakness From Impaired Spatial Awareness: A Helping Hand!

Our patient, aged 73 years, had background peripheral neuropathy of unknown cause, stable for several years, which caused some difficulty in walking on uneven ground. He attended for a teaching session but now staggered in, a new development. He had apparent weakness of his right arm, but there was difficulty in distinguishing motor weakness from impaired spatial awareness suggestive of parietal lobe dysfunction. With the patient seated, eyes closed, and left arm outstretched, S.A.R. lifted the patient’s right arm and asked him to indicate when both were level. This confirmed motor weakness. Urgent computed tomographic scan confirmed left subdural haematoma and its urgent evacuation rapidly resolved the patient’s symptoms. Intrigued by our patient’s case, we explored further and learnt that in rehabilitation medicine, the awareness of limb position is commonly viewed in terms of joint position sense. We present recent literature evidence indicating that the underlying mechanisms are more subtle

Stationary Regime of Random Resistor Networks Under Biased Percolation

The state of a 2-D random resistor network, resulting from the simultaneous evolutions of two competing biased percolations, is studied in a wide range of bias values. Monte Carlo simulations show that when the external current $I$ is below the threshold value for electrical breakdown, the network reaches a steady state with a nonlinear current-voltage characteristic. The properties of this nonlinear regime are investigated as a function of different model parameters. A scaling relation is found between $/_0$ and $I/I_0$, where $$ is the average resistance, $_0$ the linear regime resistance and $I_0$ the threshold value for the onset of nonlinearity. The scaling exponent is found to be independent of the model parameters. A similar scaling behavior is also found for the relative variance of resistance fluctuations. These results compare well with resistance measurements in composite materials performed in the Joule regime up to breakdown.Comment: 9 pages, revtex, proceedings of the Merida Satellite Conference STATPHYS2