Directing store flyers to the appropriate audience

Grocery shoppers were questioned about the frequency of purchasing items that were featured in the store's flyers. This measure was used as the dependent variable in a multinomial logit model with the independent variables being various aspects of shopping behaviour, usage of store flyers, age and employment status. Since only one threshold parameter was significant, the four-level dependent variable was then collapsed and a binary model was estimated. This study evidenced that less than half of the respondents looked forward to receiving unsolicited flyers. Most shoppers read the flyers only to be informed of price specials that the store has to offer. The odds ratio of responding to store flyer deals among those who look forward to sales flyers is more than double the odds ratio of those who do not await the flyers, across every category of shopping frequency. Retailers could employ direct marketing to target specific audiences who look forward to receiving store flyers.\u

Non-stochastic behavior of atomic surface diffusion on Cu(111) at all temperatures

Atomic diffusion is usually understood as a succession of random, independent displacements of an adatom over the surface's potential energy landscape. Nevertheless, an analysis of Molecular Dynamics simulations of self-diffusion on Cu(111) demonstrates the existence of different types of correlations in the atomic jumps at all temperatures. Thus, the atomic displacements cannot be correctly described in terms of a random walk model. This fact has a profound impact on the determination and interpretation of diffusion coefficients.Comment: 5 figure

Phase diagrams and universality classes of random antiferromagnetic spin ladders

The random antiferromagnetic two-leg and zigzag spin-1/2 ladders are investigated using the real space renormalization group scheme and their complete phase diagrams are determined. We demonstrate that the first system belongs to the same universality class of the dimerized random spin-1/2 chain. The zigzag ladder, on the other hand, is in a random singlet phase at weak frustration and disorder. Otherwise, we give additional evidence that it belongs to the universality class of the random antiferromagnetic and ferromagnetic quantum spin chains, although the universal fixed point found in the latter system is never realized. We find, however, a new universal fixed point at intermediate disorder.Comment: 10 pages, 10 figure

Optimal Forest Rotations with Environmental Values and Endogenous Fire Risk

This paper develops a model that solves for the optimal economic harvest rotation problem to maximize revenue of an even-aged forest plantation when there is a risk of a catastrophic forest fire. The paper also investigates the feasibility of using fire prone stands for carbon sequestration and estimates the effects that it would have on the optimal management regime and rotation age empirically using a typical Douglas-fir stand in the Pacific Northwest. The model incorporates risk-reducing management practices that allow risk and growth to be endogenous, and the optimal rotation model is solved using numerical simulation techniques. Results show that higher carbon prices increase the rotation length regardless of the probability of fire and that the frequency of risk-reducing management practices increase as the stand approaches the optimal harvest age. Results also indicate that intermediate fuel treatments can provide economical and environmental benefits, even with a high probability of fire.Carbon sequestration, Stochastic risk, Forest management, Optimal rotation, Silviculture, Forest fires, Climate change, Resource /Energy Economics and Policy,

Tail Dependence among Agricultural Insurance Indices: The Case of Iowa County-Level Rainfalls

Index insurance has been promoted as a cost-effective risk management alternative for agricultural producers in developing countries. In this paper, we ask whether spatially separated weather variables commonly used in index insurance design, such as rainfall at different weather stations within a defined geographical area, are more highly correlated at the tails. As a case study, we assess the degree of tail dependence exhibited by Iowa June county-level rainfalls using copulas. We search among various candidate bivariate copulas and, using goodness-of-fit for copulas, attempt to identify the copula structures that best explain the nature of dependence among rainfalls in adjacent counties. Our results provide strong evidence that lower tail dependence exists in most of adjacent county-level rainfalls in Iowa. The results also suggest that patterns of tail dependence differ across counties.tail dependence, copulas, index insurance, weather indices, Risk and Uncertainty,