Periodic orbits for three particles with finite angular momentum

We present a novel numerical method to calculate periodic orbits for dynamical systems by an iterative process which is based directly on the action integral in classical mechanics. New solutions are obtained for the planar motion of three equal mass particles on a common periodic orbit with finite total angular momentum, under the action of attractive pairwise forces of the form $1/r^{p+1}$. It is shown that for $-2 < p \le 0$, Lagrange's 1772 circular solution is the limiting case of a complex symmetric orbit. The evolution of this orbit and another recently discovered one in the shape of a figure eight is investigated for a range of angular momenta. Extensions to n equal mass particles and to three particles of different masses are also discussed briefly.Comment: 6 pages, 7 figures. Accepted for publication in Physics Letters

Conservation: From Voluntary Restraint to a Voluntary Price Premium

This paper investigates how concern for the environment translates into predictable patterns of consumer behavior. Two types of behavior are considered. First, individuals who care about environmental quality may voluntarily restrain their consumption of goods and services that generate a negative externality. Second, individuals may choose to pay a price premium for goods and services that are more environmentally benign. A theoretical model identifies a symmetry between such voluntary restraint and a voluntary price premium that mirrors the symmetry between environmental policies based on either quantities (quotas) or prices (taxes). We test predictions of the model in an empirical study of household electricity consumption with introduction of a price-premium, green-electricity program. We find evidence of voluntary restraint and its relation to a voluntary price premium. The empirical results are consistent with the theoretical model of voluntary conservation.

The economic forces driving the costs of food safety regulation

The cost of compliance with the Pathogen Reduction Hazard Analysis Critical Control Program (PR/HACCP) rule of 1996 has been controversial from the time it was first proposed. Recent survey evidence indicates costs of about $0.01 per pound. These estimates may capture actual costs but do not indicate how different components of the rule itself, such as HACCP tasks, and indirect influences, such as plant size, affect costs differently. The purpose of this paper is to empirically examine these direct and indirect influences. Preliminary results suggest that plant size has a small, if any influence on costs. The most substantial direct cost is the cost of performing sanitation and tasks associated with a plant's HACCP process control plan.Food Consumption/Nutrition/Food Safety,

For Rich or for Poor: When does Uncovered Interest Parity Hold?

We present a model that simultaneously explains why uncovered interest parity holds for some pairs of countries and not for others. The flexible-price two-country monetary model is extended to include a consumption externality with habit persistence. Habit persistence is modeled using Campbell Cochrane preferences with ‘deep’ habits along the lines of the work of Ravn, Schmitt-Grohe and Uribe. By deep habits, we mean habits defined over goods rather than countries. The negative slope in the Fama regression arises when monetary instability is low and the precautionary savings motive dominates the intertemporal substitution motive. When monetary instability is high, the Fama slope is positive in line with uncovered interest parity. The model is simulated using the artificial economy methodology for 34 currencies against the US dollar. We conclude that, given the predominance of precautionary savings, the degree of monetary instability explains whether or not uncovered interest parity holds.Monetary instability; Uncovered interest parity; Forward biasedness puzzle; Carry trade; Habit persistence

Piloting mobile mixed reality simulation in paramedic distance education

New pedagogical methods delivered through mobile mixed reality (via a user-supplied mobile phone incorporating 3d printing and augmented reality) are becoming possible in distance education, shifting pedagogy from 2D images, words and videos to interactive simulations and immersive mobile skill training environments. This paper presents insights from the implementation and testing of a mobile mixed reality intervention in an Australian distance paramedic science classroom. The context of this mobile simulation study is skills acquisition in airways management focusing on direct laryngoscopy with foreign body removal. The intervention aims to assist distance education learners in practicing skills prior to attending mandatory residential schools and helps build a baseline equality between those students that study face to face and those at a distance. Outcomes from the pilot study showed improvements in several key performance indicators in the distance learners, but also demonstrated problems to overcome in the pedagogical method