Measuring Network Effects in a Dynamic Environment

This paper proposes methods for identifying indirect network effects with dynamically optimizing consumers purchasing a durable hardware good and associated software. We apply this model to a data drawn from the DVD player and titles markets. We observe model-level prices, sales and characteristics of DVD players and sales and availability of DVDs at the level of the month for 10 years. We augment these aggregate data with household survey data on player holdings. In our model, forward looking consumers buy possibly multiple DVD players over time and benefit from the evolution of the titles market. We address issues of clustering, spurious correlation and endogeneity

Digital Rights Management and the Pricing of Digital Products

Digital products such as movies, music and computer software are protected both by self-help measures such as encryption and copy controls, and by the legal right to prevent copying. We explore how digital rights management and other technical protections affect the pricing of content, and consequently, why content users, content vendors, and antitrust authorities might have different views on what technical capabilities should be deployed. We discuss the potential for collusion through technology

Wastewater Treatment Plant Influences On Macroinvertebrate Assemblage, Functional Feeding Groups, And Productivity

Organic waste from municipal wastewater treatment plants can alter stream benthic communities by contributing allochthonous energy sources as well as altering stream physicochemical habitat parameters. Nutrients may have a large impact on the primary and secondary production of receiving streams. The purpose of this study is to evaluate the impacts of wastewater treatment plant effluents on headwater systems in the Southern Appalachian Mountains. To do this the biological, physical, and chemical aspects along multiple stream continuums were analyzed. Aquatic invertebrates were collected using a modified NCDEQ macroinvertebrate sampling protocol and keyed to the lowest possible taxonomic level. Benthic invertebrate data were used to compute community BI scores, diversity indices and the percentage of trophic feeding guilds. Benthic communities in impacted streams did not follow the RCC predicted feeding group distributions. Overall trends among impacted sites were variable and community structure was likely affected by increased ion concentrations, increased nutrients, and increased levels of primary production at effluent-impacted sites. Principal component analyses using invertebrate metrics and water chemistry parameters revealed distinctions between reference and impacted streams, and non-metric dimensional scaling plots showed that temperature, conductivity, and multiple dissolved ions significantly differentiate these sites

Green Communities Vision

This document describes the Green Vision Plan created by and for the villages of Monee, Peotone, University Park, and Governors State University. The document includes the mission statement, goals, and objectives of the plan as well as a list of participants, a 2003 letter sent to the FAA, community descriptions, and a glossary of terms