Etching of random solids: hardening dynamics and self-organized fractality

When a finite volume of an etching solution comes in contact with a disordered solid, a complex dynamics of the solid-solution interface develops. Since only the weak parts are corroded, the solid surface hardens progressively. If the etchant is consumed in the chemical reaction, the corrosion dynamics slows down and stops spontaneously leaving a fractal solid surface, which reveals the latent percolation criticality hidden in any random system. Here we introduce and study, both analytically and numerically, a simple model for this phenomenon. In this way we obtain a detailed description of the process in terms of percolation theory. In particular we explain the mechanism of hardening of the surface and connect it to Gradient Percolation.Comment: Latex, aipproc, 6 pages, 3 figures, Proceedings of 6th Granada Seminar on Computational Physic

Viruses without vaccines, or valuing indigenous research? The tensions of introducing Western research assessment practices into an indigenous university

Over my past twenty-five years of educational practice, I have striven to develop a better understanding of indigenous ways of being and doing (in New Zealand’s case, this involves the values and knowledge of Māori). I have done this by visiting and occasionally staying on marae (Māori gathering-places); by reading relevant literature; by engaging in conversations with knowledgeable scholars and by researching the impact of Western practices on indigenous peoples. In 2003 I managed a research team for Te Wānanga o Aotearoa, a Māori tertiary institution with branches across the country. Our Tertiary Education Commission had just introduced a variation of the English RAE, called the Performance-Based Research Fund, through which government research funds would henceforth be distributed. In collaboration with Māori colleagues, we chose to enter this process, believing that Māori research would be recognised and funded by our participation. While this proved to be the case, there were significant examples of values clashes, such as the requirement for people to ‘boast’ of their research achievements in a context where such boasting is anathema; to claim ownership of knowledge where tradition often indicates that knowledge is not the property of individuals; and worst, at one point I found myself accused by my Māori manager of introducing ‘viruses without vaccines’. By this he meant Westernised ideas and practices which appeared to be benevolent but in fact were toxic (the idea derives from white settlers who apparently gave native Americans blankets permeated with a virus, causing thousands to die). In this paper I will explore tensions of operating cross-culturally, and whether/how we can protect people from unintended toxic consequences of intended benevolent actions

Revisiting the Value of Research

Sure, they’re interesting research stories. But what does research really mean to UNLV, to the community, and to you

Bargaining with Uncertain Value Distributions

This paper studies a bargaining model in which the seller is uncertain about which distribution the buyer's values are drawn from. The distribution of the buyer's values is fixed across periods, while the buyer’s values are drawn independently from the distribution each period. In the classical model of repeated bargaining where the buyer’s value is drawn from a commonly known distribution and fixed across periods, the high-value buyer has a strong incentive to conceal his value, and the seller loses most of her bargaining power. An important question is whether adding a layer of uncertainty makes the high-value buyer more willing to accept high-price offers and improves the seller’s revenue. We find this to be the case as long as the seller’s ex ante beliefs are sufficiently optimistic.Repeated Bargaining, Uncertain Value Distributions, Revenue Comparison, Learning

Uniform Value in Recursive Games

We address the problem of existence of the uniform value in recursive games. We give two existence results. (i) The uniform value is shown to exist if the state space is countable, the action sets are finite and if, for some a > 0, there are finitely many states in which the limsup value is less than a. (ii) For games with non-negative payoff function, it is sufficient that the action set of player 2 is finite. The finiteness assumption can be further weakened.

Global trends in large-value payments

Globalization and technological innovation are two major forces affecting the financial system and its infrastructure. Perhaps nowhere are these trends more apparent than in the internationalization and automation of payments. While the effects of globalization and technological innovation are most obvious on retail payments, the influence is equally impressive on wholesale, or interbank, payments. Given the importance of payments and settlement systems to the smooth operation and resiliency of the financial system, it is important to understand the potential consequences of these developments. This article presents ten major long-range trends in the settlement of large-value payments worldwide. The trends are driven by technological innovation, structural changes in banking, and the evolution of central bank policies. The authors observe that banks, to balance risks and costs more effectively, are increasingly making large-value payments in real-time systems with advanced liquidity-management and liquidity-saving mechanisms. Moreover, banks are settling a larger number of foreign currencies directly in their home country by using offshore systems and settling a greater number of foreign exchange transactions in Continuous Linked Settlement Bank or through payment-versus-payment mechanisms in other systems. The study also shows that the service level of systems is improving, through enhancements such as longer operating hours and standardized risk management practices that adhere to common standards, while transaction fees are decreasing. Payments settled in large-value payments systems are more numerous, but on average of smaller value. Furthermore, the overall nominal total value of large-value payments is increasing, although the real value is declining.Payment systems ; Electronic funds transfers ; Banks and banking - Automation ; Interbank market ; Globalization