Stochastic multiplicative processes with reset events

We study a stochastic multiplicative process with reset events. It is shown that the model develops a stationary power-law probability distribution for the relevant variable, whose exponent depends on the model parameters. Two qualitatively different regimes are observed, corresponding to intermittent and regular behaviour. In the boundary between them, the mean value of the relevant variable is time-independent, and the exponent of the stationary distribution equals -2. The addition of diffusion to the system modifies in a non-trivial way the profile of the stationary distribution. Numerical and analytical results are presented.Comment: 8 pages, 3 figures. To appear in Phys. Rev.

Local versus organic: a turn in consumer preferences and willingness-to-pay

Demand for local food in the United States has significantly increased over the last decade. In an attempt to understand the drivers of this demand and how they have changed over time, we investigate the literature on organic and local foods over the last few decades. We focus our review on studies that allow comparison of characteristics now associated with both local and organic food. We summarize the major findings of these studies and their implications for understanding drivers of local food demand. Prior to the late 1990s, most studies failed to consider factors now associated with local food, and the few that included these factors found very little support for them. In many cases, the lines between local and organic were blurred. Coincident with the development of federal organic food standards, studies began to find comparatively more support for local food as distinct and separate from organic food. Our review uncovers a distinct turn in the demand for local and organic food. Before the federal organic standards, organic food was linked to small farms, animal welfare, deep sustainability, community support, and many other factors that are not associated with most organic foods today. Based on our review, we argue that demand for local food arose largely in response to corporate cooptation of the organic food market and the arrival of “organic lite.” This important shift in consumer preferences away from organic and toward local food has broad implications for the environment and society. If these patterns of consumer preferences prove to be sustainable, producers, activists, and others should be aware of the implications that these trends have for the food system at large

Bioeconomic Modeling of the Invasive Aquatic Plants Hydrilla verticillata (hydrilla), Eichhornia crassipes (water hyacinth), and Pistia stratiotes (water lettuce) and their impacts on angler effort on Florida lakes

The invasive aquatic plants Hydrilla verticillata (hydrilla), Eichhornia crassipes (water hyacinth), and Pistia stratiotes (water lettuce) have the potential to negatively impact recreational use of Florida lakes if consistent, adequate control expenditures are not made. In the mid-1990's, Florida significantly reduced its spending on invasive aquatic plant control measures, which resulted in a significant increase in needed control expenditures in subsequent years. This paper attempts to formalize a relationship between coverage of these invasive aquatic plants and angler effort on Florida lakes using data on 38 lakes over 20 years. Estimated regression coefficients are used to simulate control alternatives, and expenditure cost-benefit comparisons are made.Hydrilla, water hyacinth, water lettuce, bioeconomic, invasive, control, Resource /Energy Economics and Policy,

Availability, Attitudes and Willingness to Pay for Local Foods: Results of a Preliminary Survey

This paper presents the results of a preliminary intercept survey of consumers at farmers' markets in Gainesville, Florida in 2007. We developed survey questions to identify: (1) how much fruit and vegetable produce respondents buy from local sources; (2) attitudes regarding local foods; (3) definitions of local by distance and ownership; (4) WTP for local foods; (5) perceptions of the availability and cost of local products; and (6) demographic information. In addition to WTP, we employed several tools- a Likert scale, a cost/availability matrix, and other investigatory and demographic questions - to analyze factors affecting purchasing decisions. These include relative cost, accessibility, attitudes and perceptions of the term 'local.' We report and describe the results of the survey, including a regression analysis of WTP as a function of attitudinal, behavioral, and demographic variables. Given the small sample size, the results are largely not statistically significant. Yet, they are useful for refining the survey instrument for a larger study.Food Consumption/Nutrition/Food Safety,

Evaluating the Potential for Technology Adoption in Mitigating Invasive Species Damage and Risk: Application to Zebra Mussels

Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

European Union Farm Policy for Citrus, Tomatoes, and Dairy

European Union (EU) consumers pay almost twice the competitive world price for many agricultural products. Agricultural subsidies accounted for almost half of the EU's total budget (US$ 40 billion on agriculture in 2000) although agriculture represented 1.7 percent of the EU's GDP and employs 4.3% of the EU's population. Domestic policies for citrus and tomatoes include export refunds, product withdraws from the market, intervention thresholds, and direct producer aid. Domestic policies for dairy include export refunds, intervention thresholds, aid for private storage, disposal aid, and milk quotas. The EU's intentions are to enhance agricultural competitiveness by setting product intervention as "a real safety net measure, allowing EU producers to respond to market signals while protecting them from extreme price fluctuations," and promoting market oriented, sustainable agriculture by finishing the transition from product support to producer support, by introducing a "decoupled system of payments per farm" which are not connected to production. The EU wishes to allow flexibility in production, but also guarantee income stability to producers. Within the last 10 years, the EU has reduced price supports and increased direct payments to tomato, dairy, and citrus farmers to compensate them for the reductions.Agricultural and Food Policy,