Intermolecular Forces and the Glass Transition

Random first order transition theory is used to determine the role of attractive and repulsive interactions in the dynamics of supercooled liquids. Self-consistent phonon theory, an approximate mean field treatment consistent with random first order transition theory, is used to treat individual glassy configurations, while the liquid phase is treated using common liquid state approximations. The transition temperature $T^{*}_{A}$, the temperature where the onset of activated behavior is predicted by mean field theory, the lower crossover temperature $T_{c}^{*}$ where barrierless motions actually occur through fractal or stringy motions, and $T^{*}_{K}$, the Kauzmann temperature, are calculated in addition to $T^{*}_{g}$, the glass transition temperature that corresponds to laboratory cooling rates. Both the isobaric and isochoric behavior in the supercooled regime are studied, providing results for $\Delta C_{V}$ and $\Delta C_{p}$ that can be used to calculate the fragility as a function of density and pressure, respectively. The predicted variations in the $\alpha$-relaxation time with temperature and density conform to the empirical density-temperature scaling relations found by Casalini and Roland. We thereby demonstrate the microscopic origin of their observations. Finally, the relationship first suggested by Sastry between the spinodal temperature and the Kauzmann temperatures, as a function of density, is examined. The present microscopic calculations support the existence of an intersection of these two temperatures at sufficiently low temperatures.Comment: Submitted to J. Phys. Chem. A, June 2007 Replaced with accepted version Sept. 200

Sustainability, Externalities and Economics: The Case of Temperate Perennial Grazing Systems in NSW

The replacement of perennial grass species by undesirable annual grass weeds not only results in lower productivity but is also contributes to a range of external costs. In particular, shallow rooted annuals result in greater deep drainage and therefore a greater potential for salinity, and greater volumes of runoff of poor quality water to streams. In this paper an economic framework for examining the sustainability issues of a perennial grazing system on the NSW Central Tablelands is presented. This involves a combination of simulation and dynamic programming models, with the state of the system represented by variables for the perennial grass composition and soil fertility. The paper examines a range of management strategies that increase the perennial grass composition in terms of net income from grazing, and the impact upon the externalities.perennial pasture, sustainability, externalities, bioeconomic modelling, dynamic programming, Research and Development/Tech Change/Emerging Technologies, 160,

Generalized search-theoretic models of monetary exchange

This paper extends the literature on search-theoretic models of money in several ways. It provides results for general bargaining parameters, whereas previous papers consider only special cases. It also presents one version of the model in which agents holding money cannot produce and another in which they can. The former has been used in essentially all the previous literature, although the latter seems more natural for some purposes and avoids several undesirable implications. Since very little is known about this version, the authors analyze it in detail.Monetary theory

Administrative Performance of “No-Fault” Compensation for Medical Injury

No-fault is the leading alternative to traditional liability systems for resolving medically caused injuries, and policy interest in such reform reflects numerous concerns with the traditional tort system as it operates in the medical field through malpractice insurance. The administrative experience of the Florida and Virginia no-fault programs is examined

The business cycle and the life cycle

The paper documents how cyclical fluctuations in market work vary over the life cycle and then assesses the predictions of a life-cycle version of the growth model for those observations. The analysis yields a simple but striking finding. The main discrepancy between the model and that data lies in the inability of the model to account for fluctuations in hours for individuals in the first half of their life cycle. The predictions for those in the latter half of the life cycle are quite close to the data.Business cycles ; Hours of labor

General Equilibrium with NonConvexities, Sunspots and Money

We study general equilibrium with nonconvexities. In these economies there exist sunspot equilibria without the usual assumptions needed in convex economies, and they have good welfare properties. Moreover, in these equilibria, agents act as if they have quasi-linear utility. Hence wealth effects vanish. We use this to construct a new model of monetary exchange. As in Lagos-Wright, trade occurs in both centralized and decentralized markets, but while that model requires quasi-linearity, we have general preferences. Given our specification looks much like the textbook Arrow-Debreu model, we think this constitutes progress on the classic problem of integrating money and general equilibrium theory. We also use the model to discuss another classic issue: the relation between inflation and unemploymentMoney, Indivisibilities, Sunspots.

An Economic Evaluation of Research into the Improved Management of the Annual Grass Weed Vulpia in Temperate Pastures in South-Eastern Australia

NSW Agriculture has a history of research investment in managing weed problems in the temperate pasture areas. One focus of that research has been on the development of improved management practices for the major annual grass weed vulpia. Recent surveys have found that weeds comprised up to 80% of pasture biomass in some temperate areas and that typical vulpia contents are between 30 and 40% of pasture biomass. Temperate pasture degradation is recognised as being a major contributor to the wider environmental problems of soil erosion, salinity and acidity. This evaluation related to a project (1996-2002) that focussed on the vulpia problem in the New South Wales temperate pasture areas. The benefits of that research were measured as the difference in the economic returns from the project (the with-research scenario) and those that would have resulted if the project had not been initiated (the without-research scenario). The results indicated high levels of economic benefits from the vulpia project. The annual net project benefit had a mean value of $58 million. The benefit-cost analysis generated a mean NPV of$196.9 million and a mean BCR of 22.2. These results demonstrate that research by NSW Agriculture into the improved management of vulpia has the potential to generate substantial long-term economic benefits. Other socio-economic aspects of the results showed that wool producers outside the New South Wales temperate areas lost economic surplus (from a mean -$21.7 million to -$47.8 million) because they were unable to adopt the cost-reducing technology and faced a reduced wool price. All wool consumers gained from vulpia research because of expanded wool production and lower wool prices. Improved vulpia management is also considered to produce important environmental benefits by encouraging a greater use of deep-rooted perennial grasses and the beneficial effects of these on mitigating soil problems and reducing water table discharges.benefit cost analysis, research evaluation, annual grass weeds, vulpia, Research and Development/Tech Change/Emerging Technologies, Q160,

General Equilibrium with Nonconvexities, Sunspots, and Money

We study general equilibrium with nonconvexities. In these economies there exist sunspot equilibria without the usual assumptions needed in convex economies, and they have good welfare properties. Moreover, in these equilibria, agents act as if they have quasi-linear utility. Hence wealth effects vanish. We use this to construct a new model of monetary exchange. As in Lagos-Wright, trade occurs in both centralized and decentralized markets, but while that model requires quasilinearity, we have general preferences. Given our specification looks much like the textbook Arrow-Debreu model, we think this constitutes progress on the classic problem of integrating money and general equilibrium theory. We also use the model to discuss another classic issue: the relation between inflation and unemployment.

General equilibrium with nonconvexities, sunspots, and money

We study general equilibrium with nonconvexities. In these economies there exist sunspot equilibria without the usual assumptions needed in convex economies, and they have good welfare properties. Moreover, in these equilibria, agents act as if they have quasi-linear utility. Hence wealth effects vanish. We use this to construct a new model of monetary exchange. As in Lagos-Wright, trade occurs in both centralized and decentralized markets, but while that model requires quasilinearity, we have general preferences. Given our specification looks much like the textbook Arrow-Debreu model, we think this constitutes progress on the classic problem of integrating money and general equilibrium theory. We also use the model to discuss another classic issue: the relation between inflation and unemployment.Equilibrium (Economics) ; Money

The search-theoretic approach to monetary economics: a primer

The authors present simple versions of models used in the search-theoretic approach to monetary economics. They discuss results on the existence of monetary equilibria, the potential for multiple equilibria, and welfare. Using bilateral bargaining theory, they consider models where prices are fixed as well as those where prices are determined endogenously. After describing the frictions necessary to construct a model where money has an essential role, they conclude by reviewing many extensions and applications in the related literatureMoney